Mills MRA two types of different brand ?

Some vendors still have a supply of NOS, USA made Mills resistors.  Vishay bought the company, in 2011, and moved production to Mexico.
The older 12w Mills have black bodies; the newer version has a brown body.  Both sound good but I prefer the older ones.
Vishay bought Mills in 2011 and they have been making them ever since, in brown. There were four, color/finish versions of the older, made in the USA, Mills wire wounds: Dull(flat) in either black or brown / shiny and smooth in either black or brown.
thank you
why you prefer the older ones: how do they sound compared to newer ?
The older Mills 12w (shiny black) has a bit more detail and has fast, clean high frequencies and is slightly lean in the upper bass although it has tight, powerful deep bass.  They also have a slight edginess in the highs.  The newer version (dull brown) is warm, not lean, slightly soft and dull, and doesn't have quite as much detail.  At least that's how I recall them from a couple years ago.
i have two types of mills mra12
- the first one is dull brown and marked : "mills 1ohm mra12f 1019"
- the second one is shiny brown and marked : "mill mra12 1ohm 1% m1713 mexico"

like these:

what is the newer between the two that " is warm, not lean, slightly soft and dull, and doesn’t have quite as much detail " (salectric cit.)?
I cant comment on how the newer ones sound compared to the older ones made in the USA but I would not call the newer brown shinny ones slightly dull and warm. I replaced the sand resistors in my Dynaduio S 25,s with them and they do not sound dull and warm to me compared to how the s 25,s sounded before quite the contrary I would call them fast, detailed, tonally correct with alot more micro dynamics.
Actually your second questions ask how do they sound along with selectric talk about the sound. I was only trying to help excuse me.

I know I’m probably jumping in here late, but I’m doing some research on resistors for a project I’m planning next year. The "Vishay Mills" is on my short list.

The older NOS "Mills" resistors are black in color.

The newer "Vishay Mills" resistors are brown in color.

The only difference I have been able to determine are that the older black "Mills" have the silver-plated copper alloy end-caps.

The newer "Vishay Mills" brown have just copper alloy end-caps (no silver). This would seem to coincide with salectric’s feedback that the older black Mills have more of a fast/clean sound in the high frequencies and lean bass.

I would personally go with the newer brown resistors for overall tonal balance unless you are really after that "silver" signature that pushes the upper mids / low highs -- or if you need to replace resistors in an old circuit that uses original Mills and need to match sonic signature.

These are the specs for the new Vishay Mills MRA resistors.

The old Mills have a slightly better top end ,due to the silver platedcaps.
the newer ones are by no means dull just less promenant in the upper treble 
the new ones seem a bit fuller ,rounder in the Bass like a tube amp 
and nice full mids depending what driver  you are using  and need to give them 
a solid 50-100 hours from. Starting to open to fully settled me .
ifyou want better still the Path Audio. Are excellent  at $30 a pop a bit steep .
that being said the French company beginning with a L  want over $100 each 
they could be slightly better still ,but I will never know . I refuse to pay that for a single resistor. Like Duelund cast they maybe fantastic but Iwoukd never spend that much $$. I had their Jam caps same everything except for the compressed 
cardboard case , which does make it better ,but maybe 5-7% and 2x + the cost.
and hopefully your cablesand electronics are up to the task, or that is a Ton of cash spent for little return. 
Not totally True ,even before 2011 Mills had black and brown finishes which I have personally used both the same quality. Jeff at Sonic craft states this on the website . The 2011 to present say Mexico and for whatever reason are not quite as precise ,possibly quality of Copper, and no longer using Silver end caps like originals which. Suspect.
when using Tantalum resistors when AN started making with brass ,not as good as silver end caps , that’s what I got out of company changing  materials 
less quality refinement. Just buy NOS from Sonic craft,or Michael Percy.
For Loudspeakers Path Audio best anything including Duelund ,Mills or anything in between $30 each but less then 1% distortion  I only use the in my speakers now .