2014 Tracker Grizzly 1648, looking for rivets to replace factory floor rivets.

[Johnnyboy11]

Older tracker grizzly with what I suspect is soaked flotation foam. I'm in the process of pulling up the floor, I want to remove the old foam and put the floor back down. I am having a hell of a time figuring out what size rivets I need, and where to buy them. I am carefully removing the old ones to keep the holes in tact, so assuming I can use the same size as factory. Thanks in advance if anyone can tell me what I need.