If your oil pressure was normal then just do a maintenance check for wear. Here is a link to the online manual for that test:
http://cygnusx1.net/Supra/Library/TS...aspx?S=LU&P=10
If you buy a used part on eBay you would be wise to perform the same test anyway. It's possible there might be a new old stock one out there but it's going to cost you several hundred dollars unless you are lucky. Driftmotion is back ordered as of this writing and their upgraded pump is $335.
I use Permatex Ultra Black RTV silicone for all oil sealing on the Supra and that includes: oil pan, valve covers, transmission sections, differential cover.