Frank.
For a layman it is hard visually to see any outside differences between the two types VIIC and VIIC/41. The latter some tens of cms longer overall, mainly due to the atlantic bow which I guess is incorporated in the Revell Kit. The main difference is, as you say the stronger pressurehull and increased max. divingdepth. The stronger pressurehull increased the weight and as no change was made as to the mainengines some efforts was made to compensate this by removing and/or make lighter equipment whenever possible, but again no visible items. It might be that the max speed would be a fraction of a knot lower, but we did`t notice much difference. Some are of the opinion that the VIIC/41 had the new compass housing in front of the tower, generally not so, U 995 had the old rounded type although they have substituded this with the new type on the museums U-995, don`t use the museums U-995 as a reference as many details are unfortunately not correct.
The trouble to upload the images on this site is due to an upgrading they just had whereby all the images disappeared. They are busy with the problem, but I guess it`s difficult to resolve. As a substitute they are going to make some sort off a gallery they told me.
If you are in need of any images on my thread let me know and I get it for you.
Tore