Brakes: hill holder - left hand drive vs right hand drive

[fh4ever]

hi folks
regarding my '39 Commander.....
About 10 years ago, I was sold a NOS "right hand drive" hill holder (no LH drive hill holders were available) so I could get the ball cage out of it. The rubber sealing valve (in the ball cage) in mine was bad and I was told I the cage was the same but the cast housing was different.
Fast forward to today.... I dug this hill holder out of storage and started to disassemble it to get the cage out of it and I noticed the entire hill holder assembly looks identical to the one I took off of the car. I was expecting a mirror image of the casting and its ports. The castings even had the same wagner #FD 4211 .
My question is....is there a LH and RH hill holders? were the castings the same? Could I have a left hand drive unit? or is the cage in it upside down to make it a RH unit?
The "round nut " is so hard to get off in order to get the cage out, I prefer not to disassemble it if this hill holder is a LH unit. Anyone know the differences? Any help would be appreciated.

[r1lark]

If I remember correctly, there is a rubber seat on one end of the cage. You have probably tried this, but can you hold the no-rol unit and tilt it one way then the other and hear any difference when the ball comes to the end of the cage? If so, you can do this to both no-rol units and perhaps tell if the cage is installed the same way or opposite (ie, 'upside down'). I agree, these are so hard to get apart.

[fh4ever]

thanks Paul, I have the old cage out...and the rubber seal is to the rear. if you rotate the cage upside down, and tip the cage so the ball rolls, the ball will still hit the rubber seal, just off center a little. There are 3 rods that hold the ball in....two on the bottom...and one on top. With the unit level and horizontal, I did rock it side to side and did not hear the ball, but when I flipped the HH upside down...the single top rod should now be on the bottom. again I rocked it side to side and then you can hear the ball. This tells me the ball is pivoting over the single rod (now on the bottom). Unless anyone else chimes in, I believe the so called RH drive HH is indeed a left hand drive hill holder....just what I need. I may rig up some compressed air to it to verify.
I did find another marking on the casting...it had the single digit "5" on it while mine has "6". could be a revision number???
Also strange, I discovered in the chassis catalog...there are 3 different part numbers for early and late '39 commander and for the '39 right hand drive. I tried searching for the Wagner part numbers and came up empty.