Pre-L is just a "trim level" name the hobby has given a particular model, because it lacked any other way to differentiate or designate it in conversation from other versions of the Pantera.
Push button is not a factory designation either.
Both are unofficial names or designations for that particular version, nothing to get too worked up over.
If I told you my friend just bought a Pantera, you might be inclined to ask "which version". If I answered you "its just a pantera" it would not satisfy you. But if I tell you "its a Pre-L" then you know exactly which version I'm talking about.
In the circles I hang-out in, pre-L designates any '71 - '73 Pantera that doesn't have pushbutton doors and didn't originaly have the large black L model bumpers.
The L model features 5 mph safety bumpers and a low emission motor, these features were mandated by the US government for sales in the 1973 model year. The first L model Panteras were manufactured in August 1972, 1 month into the 1973 production year, which began on July 1 1972. The Panteras built in July of that year before the factory commenced installing 5 mph bumpers, are technically 1973 Pre-L models.
cowboy from hell