All of them I have ever gotten with an RJ connector have MX, there are a couple hard to find ps/2 models that do, none with usb those are all domes. If it's doubleshots, it's MX and that is it more or less. Just take a puller with you if you have trouble telling doubleshots on sight. The yellow arrows give it away on 90% of them. It's still good to take a puller, if you want to focus on getting just the older ones with the thick caps when going to local recycler. Ebay will still be a crapshoot on thickness of caps.
Models I know for sure: Wy30-75, WY-PCE***.
