Hi Alan,
Difficult to be certain of identification without without seeing your sketch and knowing more details. It was certainly a favorable libration. Your best bet is the NASA Dial-a-Moon Phase and Libration 2019 website, which replicates phase and libration for whatever time you enter:
https://svs.gsfc.nasa.gov/4442
If you enter the date and time of your observation and then press the update button, the image will change to reflect the Moon’s appearance at that time. If you then click on the image you can download a detailed and zoomable image that should be identical to what you saw in your eyepiece and which identifies craters near the terminator. That should solve your problem.
Good luck!
Bill