Sounds like my DS at that age...good at puzzles, fascination with buckles...as an infant he would examine the mechanisms and snap/unsnap repeatedly. If he saw someone else's carseat he would make a beeline for it so he could examine the buckles. Loved those wooden high chairs in restaurants, the straps kept him entertained. He loved the Tupperware shape sorter thing that looks like a ball that splits in half and did it like it was no big deal at around your DS's age. He was quiet and laid back and fascinated by figuring out his toys and everything in the house.
He also crawled at 8 months, walked at 10 months...but for what it's worth he is now behind in terms of motor development and is diagnosed with "developmental coordination disorder" with a "physically impaired" IEP with the school system. So what I'm trying to say is that for us, looking at motor milestones meant absolutely nothing in terms of predicting the future. I started to get worried about motor delays when he was 2 and not making progress. Up until then everything seemed normal. He is doing better now at age 7 but has been in and out of therapies since age 4.
Your DS could be gifted but it's really hard to say looking at a one year old, since they develop so differently and at different rates. The kids who looked more advanced than my DS as a toddler now are behind him in terms of certain things. DD (now 8) looked perfectly average until she was around 2 and her speech exploded.
