I had an experience with a three on the tree...a friend had moved to Ft. Lauderdale for a job transfer. The next year I went down for spring break, I called him and he came and partied with us. He was way too trashed to drive (as were we all) but insisted he had to go home so he could go to work in the morning. Once we got him in the van and got his address (and figured out the funky Florida streets, avenues, boulevards, etc) I put the keys in the ignition then found it was a three on the tree. Having never driven one sober, it was quite an experience making my way through the spring break crowds without stalling or running someone over while learning how to drive it. He got home safely, eventually.

The '69 service manual shows 3 on the tree (Saginaw) was an available configuration with a 6 cylinder engine (code FK)

I remember the easy way to spot a two speed if you can't see the shifter panel...look at the trans tailpiece for a big weight bolted underneath. Faster than looking at the trans pan...