The O.D. is different. It may be possible but it would be better to use the right tool. You don't want to crinkle the IMC and end up buying a new length if it doesn't work. Try it on some scrap IMC first to see if you've got the right touch to make it presentable. You're also going to be busting a gut trying to bend IMC with an EMT bender due to the thicker and stronger walls.
Can you buy a pair of factory 45s and insert them in the run?
What about the old 'buy a 1" IMC bender, use it once, clean it up, return it and get your money back' trick? Put a cloth over the IMC so it doesn't scratch the shoe, do a careful job keeping it clean and you should be able to take it back.
Benders are sized for EMT; the rigid and IMC that they bend is one size smaller.
So, you would need a 1-1/4 bender to even fit the pipe in the shoe.
I'd order the 46's and splice them in. For one piece and two bends, this is easily the cheapest way.
Otherwise, United Rentals has entered the electrical equipment rental market.
A larger contractor might be willing to bend the pipe, for a fee.
I've often made SMALL bends using a Harbor Freight hydraulic bender. Bending a 45 in IMC ought to be just barely possible. It's time consuming, and you're likely to scrap some pieces before you get it right.
The old 'return trick?' Personally, I consider it to be dishonest. Most supply houses won't play along in any case, with 'no tool return' policies posted.