upper idler interchange question

[mc_mike]

I have a 420 5 roller with the straight upper idler support. When I bought this basket case crawler it had 2 new upper rollers that came with it, along with the worn out ones that needed changed. The new parts have part number T14777T cast in the back of them, the old ones are too worn to see any numbers. When I was trying to put the new ones on, the front cover won't line up with all three holes. I have indexed the cover around and I can get 2 bolts but not three. The part number on the cover I am using is T2337T. I think I could probably elongate one hole and I think it would work but I was wondering what the issue might be? Anyone have any ideas?