I'm on the hunt for one after reading about their history recently. Any good resources or things I should be knowledgable on before purchasing?

First and foremost.....Make sure the locking block is not cracked!

It was a particular failing with the Helwan and the part (unless someone is making them again) is mostly unobtainium. The last one I saw on eBay was $125.00. Without a functioning locking block your Helwan is just a paperweight.

Stick with the .mil issue ones. The made for export ones run from barely adequate to just terrible.