Magnapan Model MG 1 compare to model ...MG 1 " IMPROVED"


I just purchased a pair of vintage Magnapan speakers
On the box and on the speakers it says MG 1 " IMPROVED"
 Trying to research:
, What is the difference between MG 1 and MG 1 IMPROVED?
I contacted Magnapan customer service advisors but they said they have not been with  the company
long enough to know  the answer
ALSO....
The speakers work great and I was wondering because they have no rattle or buzz,... that they were probably restored at one time.
what do you think ?
Thank you
rocky1313
Oh I also want to say that Magnepan is very quiet about the details of changes they make. On the current versions, they will not tell the details of the crossover changes. I suspect your loudspeakers might be in the same boat. Magnepan: "We made some changes" 
I have very fond memories of when I owned the Maggie MG1 improved back in the day. I replaced them with Acoustat 3's...which while being more expensive, larger and all electrostatic...really were not as great sounding! 
If I remember correctly, and this is from long ago, the improved were called this as they slightly changed the grill material and the stand..plus maybe had a modification to the x-over. In any rate, a super speaker that I suspect I would still enjoy today.