Unfortunately the number of G2586637 tells us nothing... BUT... I've been told that some boaters have called the techs at Bombardier and they have been able to translate what year and horsepower it belongs to... worth a try?
Normally the plate/decal is on the port side transom bracket or a heavy duty decal on the top portion of the engine's swivel bracket, or also the core plug of the engine which you have already stated.
Other than the above, I would think that you would need to post various pictures of the engine. On this topic.... the paint job on the hood is never duplicated from one year to another... never! Some good pictures of the hood/cowl (if not repainted) will reveal exactly what your engine is.
