Ok, well, um, it appears that the PO must have removed some of these internals. When I went to check the clearance, all I found was a thin metal sleeve loose inside the end of the tube- looks to be about 2" long and was just about a press fit with the end of the tube. After removing it, I measured about 6 inches from the end of the tube until I touch whatever remains inside. Is it a safe assumption that the front bearing has been removed and that I can simply press in an Okie and be good?
Thanks guys!