Palco was bought out by Hagie years ago and went under the name Stronghold.  After a few years Palco was started up again, I believe after their no compete clause expired.  Anyways Palco is still being made as is Stronghold.  By the looks of the pictures it looks like the panels all interchange.  Could be wrong on all I said, but pretty sure I am right.

http://apacheequipment.com/palco/

http://strongholdmfg.com/