Shawn.. Unfortunately, the response you got from that sales woman is typical of whats' happened in the US these days.. I was in Walmart this week and a woman asked an employee where the Dust Busters (hand held vacuum cleaner) were located.. The girl responded with "what's a Dust Buster?)... Go figure..
I should have been clearer about making your own solid mounts.. What I have done in the past was to bolt the cushioned mounts together. The rubber insert is to protect the passengers from engine vibration which can be severe, especially with a big block that has been cammed up.. I have removed the mounts, drilled thru an open area, inserted bolts with a long shank and installed the retaining lock washers and nuts to be tight so as to not collapse the rubber cushion. It gives two advantages by preventing the mounts from breaking and retains the cushion against vibration at the same time..
Keep in mind that if the mounts are collapsed by removing the rubber cushion, it could possibly affect the saddle height of the engine and drivetrain.. Also could stress the transmission mount by not sitting at the correct height..
Sometimes, we have to be creative with these older cars..
Hope this helps to get the ideas out there for you..