smle or no4

Well Thats a Personal preference ... Every one has a favorite ....  You will have to find some one with both and shoot them to see which one You prefer !!!

I would second using the No. 4 rifle as the one for shooting. Better sights for most of us, a heavier free floating barrel, mostly better trigger pull, esp. if you buy a MK 2. If your field is open, I'd go for an inter-war 1 Mk III or a postwar (WWII that is) MK 2 or MK1/3 as they are built with somewhat tighter chambers and weren't built under wartime pressure.

S.M.L.E was the #1 Mk III (& III*) the differences are largely internal, but as a shooter you'll notice the sights are very different.
The S.M.L.E. has a open notch part way down the barrel, the #4 has a rear-mounted receiver peep sight.
Handling is very different. The S.M.L.E. has a noticeably nicer balance, but for a shooter I'd go with a No4.
If it makes any difference the muzzle is very different & they take different bayonets as well. (Just in case a target really annoys you)

You can get target sights for both models, but that's a different discussion.

Yes the SMLE was a 10-rounder. AS for the bolt looking "odd" there were several versions of the rear of the cocking piece. One of them was a round "disk" at the rear, designed to make it easy to re-cock after a FTF in muddy trench conditions of WW1. This was replaced with the flat one with serrations shown on both rifles in the pics above. It could be "right" with either depending on when it was made.