If it's an "uprated" pump, as most AG pumps are, it may not be nearly as powerful as a 1.5 "full-rated" IG pump. If it's full-rated, you'd probably already see problems with it.

If it was sold as a matched pair on a common base, odds are it's OK, even if not necessarily optimal. You can probably get better filtering by replacing the filter with a bigger one, or going down to a 1/2 to 3/4 hp pump. It will save electricity, too.

However, if you are NOT having problems and your pool is clean, any change is an expense and only you can decide if it's worth it.