Unfortunately, since there aren't any monitors or provenance nazis, you can list something just on a hunch or from what someone told you (whether it is right or wrong). I can understand how naive sellers on ebay and other various sites do this and many correct their history when advised. However, when a store or high number seller does this - it is telling me that the almighty dollar is what counts.
I gotta' admit I looked up the word tat in several languages to find out what you meant. I am still confused..... Never heard a purse called a tat. (Can you explain?) I first thought of a "tatted" (needlework) item came to mind when I first read your heading and then quickly when to tattoo as well! LOL
When I put "In fact, I wonder if this is where your purse/tote came from....just transformed" I was meaning that the artisans might have been commissioned to take this style of well and convert into a "purse, tote, handbag, pocketbook, carryall". I even wondered it it was originally for carrying paintbrushes for the artisan!
The only other purses I have seen made of bamboo were from the 1930's to 1940's and they were "plain jane". Simply the Giant Bamboo was cut 1/3 to 2/3 with the 1/3 being hinged to make a lid. (I say that with respect because I don't think I could simply cut a piece to convert without some acquired skill.)