I have no idea if the wrecking yard pack is original or is another aftermarket replacement.
hmm, since you have the pack out it's not
terribly difficult to open it up part way, pull a stick out and get the serial number - on a white sticker. You'd have to pull the electronics board off, disconnect stick PTC tabs, remove orange end boards from both sides of the pack, pull one of the sticks without a thermistor attached... I don't know, it is kind of cumbersome if you haven't done it before. Otherwise, you can pull the fan shroud off and look into the pack and see what color shrink wrap there is, or maybe you can do that from the end opposite the fan...
Orange is usually older OEM, yellow is OEM, not sure from what years. I don't think any of the aftermarket packs use these colors. I think aftermarket are usually dark green (Dorman), pale green (really old Betterbattery and maybe some others), white (old Bumblebee) or black (newer Bumblebee), blue - cheap stuff, like Yabo or King Kong... Something like this, it's not cut and dried, but typically about like this...
You can also do the tap ultra deep discharge with the pack out of the car, as it is now. You do 5 taps at a time and each set of 5 can take quite a while, like maybe a week... So you're looking at a couple weeks, still, without having a pack... I think that's what I'd do - just bring it into the house or garage, set up the taps and let it go. If your car is a daily driver you can just bypass the pack that's in it - turn the pack switch off and disconnect the connectors on the 'computer on the left'...
Really, there's lots of options. You can pull the Dorman out of the car, bypass the IMA, and putz around with some of those sticks with your hobby charger gear, just for fun, if you have the spare time in the intervening weeks, while you're discharging the other. I might do that, pull that low voltage stick and see what it does 'on the bench'. Sounds like you might have that kind of hobby charger/capacity since you mention knowing about lipos or whatever... Take a look at the cell voltages, for instance, by using a pin and voltmeter, just pierce the shrink wrap. Personally I'd set up the stick monitoring pairs of cells during a charge and discharge, for example...