Well haha, there are certainly more differences than the color of the slide but YES, 745 can use a 645, 745 and 4506 magazine all happily interchangeable.

I absolutely love my 745's, I have two of them and I often mention that we just don't talk about them enough around this forum!

Love love love the 745! I think they are both underrated and in the current market... undervalued.