I'm not sure where you get that BradBURY has projected All Pro talent. That's not what NFL.com has him rated at.
https://www.nfl.com/prospects/garrett-bradbury?id=32194252-4109-2951-18e8-697b9ff5297c
They say he has a good chance to become an immediate starter, but are negative on his size and a few other things.
Look - he's a good prospect - NOT a projected All Pro. As I've argued, the Rams have many needs that are more important - and harder to fill - than center, since Allen actually played well in a small sample size last season.
I can't say whether the Rams will use pick #31 to draft C/G Bradbury. But to say he is not considered the top interior O-line prospect and potential All-Pro is a bit naive. You list only one source for your claim. I List the following ;
NFL Network:
1) Bucky Brooks lists him as his top C/G prospect
2) Danial Jeremiah lists him as the 18th best player of his top 50.
3) Lance Zierlein has Bradbury #22 overall in his latest Mock draft
The Draft Network . COM ( 4 scouts listed )
1) John Ledyard has him #6 on his TOp 200 board 2/26
2) Trevor Sikkema has him #41 on " " " 2/26
3) Kyle Crabbs has him #43 " " " 2/26
4) Joe Marino has him #11 " " " 2/25
All of these were before Bradbury had excellent testing at the Combine
2 of the guys @ CBS, R.J. White and Ryan Wilson had Bradbury @ 20 & 22 respectively in their Mock Drafts
Last, Matt Miller @ Bleacher Report has him @ 21 on his Big board
I'm not sure there is a positional group on the team that is any more important than the O-line. Offense, specifically point scoring is the Rams forte. The O-line gave holes for Gurley to run and allowed Goff time to pass. They have now lost 2/5th's of that line. The Rams have said , "We are happy to go into the offseason program with Noteboom and Allen as LG & Center". However, IMO, they may be leaving this out, "if a starting caliber player is not available in the Draft."
I will be one, and probably in the minority, that would very happy with the Rams selecting Bradbury early.