Can the Same Brand Power Tubes Have a Different Sound When Bought From Different Vendors?

The thing OP "BETTER" has to be defined by you.

If YOU think about what you want in a valve and can put that into words that the vendor understands, you're going to be miles ahead of. 
"Give me the best" or "What is the best"?

Usually valves are known more by their ability to respond to the signal and NOT distort it.. or a noisy valve subject to vibration of microphonics.

EITHER will really ruin bass duty for a valve amp.. I don't use them below 300 hz NOW. But 60-80 hz and BELOW is a real push for me.. 5-6 ohms is pushing SQ too.. 8-12 is always better for valve amps..

Can the same valves sound different because they are not matched well?

To the POINT..

Oh heck yes.. 5% or less vs 10% if your lucky. Cary HATES non matched signal valves. Just ruins the sound. BUT matched.. night and day.. Like heaven.. All the difference in the world..

That is usually WHY people weren't impressed with Mac sound, poorly matched valves.. It makes ALL the difference in the world..

Regards

@oldhvymec

To the POINT..
Oh heck yes.. 5% or less vs 10% if your lucky. Cary HATES non matched signal valves. Just ruins the sound. BUT matched.. night and day.. Like heaven.. All the difference in the world.

I've read  that the hand picked and matched tubes are matched to a lower percentage than the factory matched. has that been your experience?

@ ebm
 I was referring especially to new production tubes, not NOS (though I am considering NOS Svetlana Winged "C" 6550. Good Choice?)

@ drrsutliff
I have dealt with Jim on several occasions and I agree with your assessment.

In all the years of buying valves. I’ve been had twice. I know I’ve bought, traded and pulled 5000 valves if I’ve done ONE. A pair of RCAs twice.
12AX7s and 12AU7 (?). Same guy too.
After he knew I would CHECK his work, we never had an issue again, AND I bought 100 valve lots a few times from the guy.

5% is 5%. That is usually the issue. MY 5% is 5% or less.

Carys matching is top to bottom. Left to right will BIAS out.
Top To Top
OR
Bottom To Bottom.

BUT Top to Bottom and left to right is what makes the the amp image the way it was suppose to..

A lot of the pulls are from instruments and the two different value sections are doing TWO different things.. THUS the used valves may be half used on one half and not at ALL on the other half..

NOS is not that way.. Noisy or handled rough is a whole different thing.. It does matter, but matched valves (TOP to BOTTOM) are usually what a good matched pair reflect. Top to bottom and left to right.. 5%..or < on all 4 sections..

Be picky, it pays..it doesn’t cost to much keeping folks honest. :-)

Regards

Not really. What will make a difference is how long each set is in use.

RAM Tubes, the highest standard in tube scrutiny and grading done by any human, that human (Roger A. Modjeski) unfortunately (for us remaining here on Earth) now having moved on to a higher plane.

I'm no Roger A. Modjeski, but were he still here, he would (I believe) tell you that a tube doesn't itself have "a sound", but rather a given tube in a given circuit results in an amplifier that creates a "certain sound". For a glimpse into the wisdom possessed by Roger, read through all the postings on his still-viewable threads on the AudioCircle Music Reference Forum. I am hesitant to throw around the adjective "genius" ( I reserve that for the likes of J.S. Bach), but Roger comes damned close.