According to Damper Doctors, there are 8 different dampers for the the 327. Chevrolet used 3 different timing mark locations, Noon, 2:00 O'Clock and 2:30 O'Clock, so if you don't know, you can install the wrong clocking damper with your chain cover tab and your ignition timing will be off.
What would I do? I'd box up my damper and ship it to the good doctor for a rebuild. He will disassemble the damper, install new elastomeric material between the hub and the inertia ring, clock them properly and press the assembly together under hydraulic pressure.
The other reason to rebuild an OEM unit rather than purchase an aftermarket unit is that the hub isn't always bored to spec. You guys are aware of all the junk coming from offshore and some of these damper units are no exception. One thing about re-using your rebuilt damper, YOU KNOW IT WORKS.
Installation can be eased by putting the entire damper into a large pan of water and bringing it to 200 degrees, then pushing the hub onto the crank snout with cooking mitts. It should slide on easily, particularly if you use some ice on the crank snout before assembly, eliminating the hassle of tearing threads out of the crank with an undersize hub or having the unit not do its job from being bored oversize.
Once you have a valid damper in place, verify its validity with the timing tab by using the procedure outlined here.....
You have no way of knowing if the last guy who worked on your motor kept the stock tab and damper matched up.