Boat lift capacity for a shoremaster

[Saskboatguy]

Thinking about making an offer on the linked Kijiji add below. Not sure on weight capacity. Model number on a very faded plate says "V30VV40" from what I can tell. Get all kinds of info online saying they are 3000 or 4000 lbs. But some info says that is the "bottom base rail" is 2" X 5" (which this one is) then it's 4,000.
I need a 4K not a 3K.
Anyone have any insight on this?

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