Love their bootlegs. Back in the day - long before micro digital recorders and the internet - recordings were made of live concerts by lugging in giant tape recorders. From there, the recordings were cut onto records. A few labels were out there. One of the most prominent (in Southern California at least) was Trademark of Quality.
Earlier covers simply had the title stamped on a blank jackets.
Later, 8 x 10 Xeroxes were inserted under the shrinkwrap.
The labels had no unique writing. Just their iconic pig logo - which was selected from a clip art book of options for bank checks.