the JBs I have are at least 15 years old - would they be the "old" version?
No. It was in the mid - late 80s, I believe, that the spec was changed on the JB; higher DC resistence, higher output, and broken tone. I don't really follow SD pups' history (or sound) very well ... they just don't sound good to my ears!
If your pups are more like 23+ years old, then you may have an original. You will know because it won't have the name "Seymour Duncan" etched onto the bottom of it. It may or may not have a sticker that says "JB".
If you like your JBs, that's great -- I'm very happy for the both of you. PDT_008