help needed to identify a lock up converter

[dodgefred]

Got a torque converter for a 904 trans . Have another 904 lockup trans whitout converter..., just wondering about identify a lockup converter vs non lock up?. They look the same despite the drain plug and the notch for the pump. The one on the left is from A500( 904)which is lock up.
The second on the right has a drain hole? They dont have any number Nothing to check ,. Could some one help?

 

[dodgefred]

Picture of the splinned shaft for the lockup

 

[Battlewagon]

I believe the lockup and non-lockup have different spliine count, so you shouldn't be able to fit a non-lockup converter on a lockup trans.

 

[7mopar]

Non lockup converter can be had for lockup trans. I do not think the std lockups had drain plugs.