The part numbers do not adequately answer the question as they are different materials, thus would have different part numbers.
What I believe is the determining factor is lock up. I believe the barrels lock up into the slides and maybe also the frames differently on the 5906 and the 915, making exchanging slides not possible.
The next issue, then is whether the entire top halves will interchange, as opposed to just the slides. If the frames match up exactly, and I mean exactly, the maybe, but I would not try it.