[Collins] 32S3 variations

[David]

I have acquired two different 32S3 units which I'm trying to restore and I
discovered a variation between the two.  Underneath the chassis, one has a
shielded enclosure around V2 6U8A; the other one doesn't.  Unfortunately,
the serial numbers are not known between the two.
Can anyone describe why/when this mod was done and what performance
differences might one see?  thanks
-dave
W5OC

Unit with shield around V2
http://www.qsl.net/w5oc/32S3/v1.jpg

Other unit with no shield at V2 (yep, previous owner clipped out filter and
xtals...)
http://www.qsl.net/w5oc/32S3/v2.jpg