700r4 TC identification

[Swearbody]

I have a 700r4 that the previous owner had replaced in 2016. I discovered the 4 prong plug has been disconnected and am trying to verify if the TC is lockup capable (meaning the PO just forgot to plug it back in) or if it has been replaced with a non lockup converter.
It is a very common brand (poorking aka ProKing) and the model number is (GM18A)...When looking online I only see the (GM18AL) and wonder if the missing L declares it to be a non-lockup converter. The 18AL is verified as a lockup. Hoping the 18a is just a different stall range or something.

 

[Swearbody]

OK I found the info....This is a higher stall speed than the 18al. Im frikken scoring left and right with this truck.. Didn't know the trans was practically new and has a higher stall speed which will greatly benefit my build

 

[fast68chevy]

TCC converter have extra third small tinyy center shaft for the lockup function. look inside the converter shaft splines set for the small third center hole. 700r4 converters dont fit 350 or 400 trannies. but 350 and 400 converters interchange same. so if the converter is a TCC one but wont fit onto the 700 tranny then it probly a 350/400 one.