Jennings Research was out of Pasadena, California.
I know they made the Contrara P tower speakers in the mid 70's. FWIW, the towers went for $225 in 1975. Not sure what your Contrara bookshelf speakers went for.
For reference, the better known AR #a went for $295 and the Advent Loudspeaker was $140.
Cool find!
You like the sound, so just enjoy!
Don't play them at extreme volumes (speakers of that era usually did not handle too much power that well - especially the tweeters) and, hopefully you'll get years of enjoyment out of them (supplemented by the cool antique factor).