Any government size 1911s (5 inch models) will all have the same size grip.
There are just options for a 7 or 8 round mag for 1911s. They are the SAME size magazine - the follower is just shorter to allow the 8th round.
No, some mags have a slampad - it makes the mag longer for easier andquicker insertion.
Ah, I thought that could be the only thing that could jive with what you had said. In the long run, I guess the difference between 7 and 8 in the same size mag would be reliability?
Here's a short bit about 1911 mags to explain some of it in a little more detail:
A Quick Bit on 1911 Mags.
In the past 7 rounders were more reliable than 8 rounders - not so much now... But some old timers still prefer 7 rounders...
I have a mixture of the two... I use the Tripp rebuild kits in some mags, and they are only 7 rounders (they replace the insides with a better spring and follower)