I'm guessing that the monster 72v battery you're talking about is the Panasonic GA 72v70ah battery? I have that battery but the 72v49ah version as I wasn't sure if the 70ah will fit in my frame (they are designed for the enduro frames with plastic panels, my frame is the one with metal panels so they have narrower opening). I didn't buy the battery directly from them but instead through their AliExpress store however they took down a lot of their items from AliExpress because they were tired of people making false disputes, they only have few small items on there now.
When I did get my battery first thing I did was open it up to verify the cells (they are indeed panasonic ncr18650ga), build construction and the BMS and they are excatly as described and the build construction is excatly the same as they show on the images, they do actually have those copper plates inside. I had this battery for about 5-6 months that I use on almost daily basis (it's my daily commuter) and haven't had any issues or problems, it's been working perfectly.
The only complaint that I have is that they are not using a bluetooth BMS for that kind of battery, it would be easier to monitor the health of it and status but the BMS that they do use is active balancing which is good. Also keep in mind that the prices shown on their website is not final, they don't include tax/import duties, shipping and payment fee (no payment fee if you use bank transfer). Some of those fees are added at checkout, I'm unsure if they handle tax/import duties or if the buyer does, when I bought it from AliExpress, tax/import duties were included so it's probably the same if you buy it directly from them but you can ask them to be sure.