How do I / should I approach an old classmate I ran into?

I (20M) work at a retail shop and was standing behind the counter when I looked outside and saw someone parking who I recognized from primary school. He was only in my class during the last year. We weren’t the best of friends, but we were friends.

I recognized him immediately, but I honestly didn’t think he would recognize me. He came into the shop and asked for a product that we keep behind the counter. I got it and then he asked “are you [my name]?” and I said "yup". I kinda just laughed it off and we had a very short conversation.

I am the worst and most awkward at communicating with guys my age and I was kind of in shock that he even remembered me. He said it was great to see me again, and I just said "yeah". For the past couple of days, I’ve been rethinking about my cringe and what I could have said and what I would say if he came back. It could have gone worse I guess, but it already happened so whatever.

I have a colleague who also went to the same primary school and knew his last name. I ended up looking him up and couldn’t find any social media under his name. I think I may have found his snapchat, but I’m not sure it’s actually him.

Should I add/message him (if it's even him), or should I just leave it alone?

My intention is mainly just to reconnect and get to know him better. I’d just like to be friends with him or really just have a nice conversation even if it stays like that, since I’ve never really had many guy friends around my age and we already kinda have a start so it makes it easier (in theory maybe)?

Would it be weird to add him on snapchat out of nowhere? And if I do, what would I even say?

I could mention the fact that we saw eachother (obviously), or maybe his scooter which has a beautiful blue colour. I also remember us sharing Pokémon cards in class.

I also don't want to come across as creepy, pushy, desperate or needy. I just don't know whether I should take the opportunity to reconnect or leave it as a random encounter.