My first kit (purchased in late 1972, maybe early '73) was the long box and the kit itself had the "loop" and "peg" approach to attach the nacelles. The light kit had been phased out by the time of this release. I didn't paint anything other than the engine domes and the main "dish", and like so many other kids, I used Testors red.
This was my first experience, as well. Eventually, my paper route money purchased every ST model made... even the UFO Mystery Ship that glowed in the dark. It gave me the idea to use Testor's black-light paint for windows on the ships. When I turned on the black light at night in my room... my ships came to life.
BTW, I never knew you were supposed to put them on a shelf. I used fishing line to hang the Bird of Prey, D-7 and Enterprise from my ceiling. I went through a few sets of Galileo 7's and Spock with the snake-thingy because I PLAYED outside with them... in the grass and dirt as I "explored" our farm.
In the late 80s to early 90s, I repurchased the ships from TOS as well as TNG. The guy at the local hobby store showcased customer models and asked me to display mine. Whenever I brought in a new ship to display, he'd GIVE me another one to build. The owner said my displays sold a lot of ST models for him. [I think my OCD came into play, because I built them to near perfection... using 50-100 man hours each.] I still used black-light paint. When I was younger, I didn't know about the lighting kits... so I never used them later either.