(Pictures and manuals, below, grabbed from the Hayward pump page, here. )
There are TWO Hayward Super pumps, the "Super Pump":
and the "Super II Pump":
Here's the breakdown diagram for the Super II:
If you mean, by "seal plate", what's shown as a seal plate on this diagram, then yes, replace all the rubber. But, ALSO, you need to replace the pump seal. Make sure you see how it comes off, before you try to replace it. And, if you've never done a seal before, I'd get TWO seals, unless your local pool store is nearby AND keeps them in stock.
Another point: I've had no end of trouble, over the years, whenever I've purchased non-OEM rubber parts. I'm sure some after market maker does make quality gaskets and such, but I haven't been fortunate enough to encounter them. Personally, I now NEVER purchase non-OEM rubber parts. In your case, I'd recommend Hayward brand gaskets and such. (But, I've never had a problem with non-OEM seals.)