Oil pump.... reuse or buy new?

I had planned on buying a new one they are only about 40 bucks but I was looking and my old one and took it apart just to see how it worked and I don't see a whole lot that could go wrong or wear out. Should I just save the 40 bucks and reuse the old one?
The old one came off a 318 at they the same pressure as a 360 pump?
If a mild street engine, and I know it worked good, I've re-used them without worry. I've put new ones in also. A new melling oil pump is never a bad idea.