Cedar rib no 4 - serial number found, need help dating it


Curious about Wooden Canoes
Hello, I have started to strip the old varnish and took out the small seat plate behind the last thwart at the end of the boat. Underneath I found 5553 painted in black with a 4 under it. Since my canoe is a number 4 I assume that this is the canoe ID and the number above the 4 is the serial number. Can 5553 translate into a date?
DYI paint stripper: I do not know how applicable this is outside France but here we have a very potent cleaning powder called Saint Marc, it's actually some pine flavored sort of soda crystals. Typically used to thoroughly clean walls, kitchens etc... before redecorating. It's pretty cheap, sold in 1 kil cardboard boxes. We also use powder type glue for wallpapering, just mix with water. Now the trick is to prepare about a gallon of wallpaper glue, then drop one box of soda crystal into it, thoroughly mix. You end up with a gooey type mix that sticks to vertical surfaces thanks to the glue, forming a thick coat. Paint it all over the old varnish, let it seat for two to 6 hours, then remove the melted varnish mix with a stiff nylon brush and plenty of warm water, or a pressure washer at low pressure (tricky to use but faster), and rinse. If you leave it a few hours it will darken the wood but you can easily bleach it to regain the original color. It will remove old varnish in one or two applications, it's cheap, and it won't burn you.I just stripped 90% of the outside of my canoe and about 50% of the inside in one afternoon. If you have this sort of cleaning powder it's worth a try.