How many versions of Magnepan SMG exist?

My son bought a used pair of SMGs that are much wider than company specs indicate. Much of the width is in solid wooden "wings" on either side of the active surface.

To improve his WAF, he would like to remove most of the extra width (so they are less noticeable when in use, and can be easily "hidden" when not), but he's concerned about possible degradation
of performance.

Any info regarding this, or results from similar experimentation, please??
Three versions SMG, SMGA, SMGB, if memory serves. The purpose of the wings is to prevent the back wave from wrapping around and cancelling the front wave at bass frequencies. Diminishing the width will certainly increase this cancellation thus decreasing bass response
Viridian is right, this would be a bad idea.
You can add the SMG-c to the list as well. The original SMG version was a bit larger and heavier looking than its successors. I believe that the "a,b and c" versions were quite similar in size all being not as wide as the SMG but I could be wrong. If size is really an issue possibly a solution is a new or used pair of MMG's as I think their width may be as much as 4 inches less than the SMG on hand at present. Get out the tape measure and check Magnepan's website for the MMG measurements - maybe it will work.
I was well aware of the effects of cancellation, but assumed that perhaps since later versions are not as wide, Winey determined that reducing the width of the wings would not degrade the performance that much. Or were other changes made to later versions to compensate?

Perhaps we can work out an arrangement by which the wings can be hinged back out of the way when not needed. My son got such a good deal on the pair, I doubt he will be interested in letting them go at this point.

I appreciate all of the responses.
Rgd, thanks for the correction; I guess that memory did not serve.
You may find that the later narower versions are designed to be used exclusivly with a sub.