this engine has been disassembled down to just the block (with the expected rotating assembly still inside) or a long block (leaving the heads still attached to the block)
there's 4, maybe 5, bolts holding the timing cover to the block - not a full set. so that's easy to check out as it's already been apart.
same for the water pump. most water pump bolts are missing.
I see another head sitting on the floor in one pic. seller has other pieces and parts to turbo buick engines.
seller should welcome the opportunity to show you what's happening with this already disassembled and then partially re-assembled engine.
since seller has other engine parts laying around, need to verify the parts. don't want to find the engine did have a blueprinted TA Performance timing cover but that was swapped out with what you see there now. is that a GM timing cover or a Chinese cover with misaligned bore for the cam sensor causing the cam gear and drive unit gear to wear excessively. how bad is the quarter sized wear divot from the cam thrust button on the inside of the timing cover. if it's a gm cover, milling that wear area flat and maybe adding an epoxied wear surface plate like in the Buick PowerSource book is the solution.
with the water pump barely attached, what was there before? to remove the timing cover, one does not need to remove all the little bolts that just attach the water pump to the timing cover. maybe there was a better water pump, maybe even a FlowKooler high flow unit, that was taken off for this sale.
Again, since it's already been disassembled and partially reassembled for this sale, seller should have no problem showing you all the parts for inspection since they're barely attached with minimal fasteners.
it's not as though it's a complete engine that's never been opened before and you the buyer wants permission to take that unopened engine apart. this thing is already apart. you just don't want to discover or learn later that the good parts that were on this engine were swapped out with scrap parts laying around to make it more complete. that's an expensive lesson. where's the rest of the hardware, balancer, flexplate, headers, accessories, etc. once you get a better idea of the components and condition and history, you can go up in offer as Rich noted above.