Lennie, that does not look like the area of the cart we need to see. If I'm seeing things correctly, that looks like the "sled" that the cart attaches to and is plastic while the cart is a shiney metallic color. We need to see the top of the cart, underneath that sled to see if there are any markings that would identify it. However, that said, I have a Stanton that has NOTHING on it and if it didn't have the old stylus still on it, I never would have known that it is the 737E so there's that. We may need to do some more research but the fact that it has the stylus in it, sounds good to you, and the stylus has D7E on it pretty much tells us what you need should you decide to keep the cart and just replace the stylus. Rocket's comments about the PM4216DE stylus are also encouraging, did you see his post?
This is the only thing on the bottom of the cart. Just an "E".


So here are a few pics of the Stanton 737E that I have, very similar to your Pickering which is by all accounts, at least according to Rocket a Stanton 681. No markings other than the "Stanton" logo on the top which is hidden until you remove the cart from the sled. View attachment 2180002 View attachment 2180003 View attachment 2180004
And I just found this on VE:
https://www.vinylengine.com/turntable_forum/viewtopic.php?t=81638
Try this, because I know you are not reaching the full potential of what's available here on AK. Start a new thread and make the title something like "need help with Pickering cartridge" and see what shakes loose.....your best bet amigo.
The stylus at Amazon is most likely not the nude mounted diamond I suggested. My recommendation is to find the nude stylus.
While the cartridge looks kinda crusty, that shouldn’t impact the sound. I bet some careful cleaning with metal polish would make it shine.
The other cartridges mentioned are lateral moves, at best.
Why not go with an Audio Technica AT95 cartridge with a HE stylus. More affordable and highly regarded.
https://www.lpgear.com/product/ATVM95EN.html