The problem is that it only shows 256K of chip ram and 512K of fast ram. The front memory isn't there.
Where is that 512k of fast RAM coming from? Anything connected externally? The stock A1000 does not have any internal memory other than 256k (+256k via A1050 or compatible) of chip RAM.
(Uneducated guess: I don't see enough chips added on the piggyback to make up 512k, the 74F08 is no RAM, and the other one is not recognizable)
Edit: In one of your follow-ups you state that the machine couldn't load kickstart - how did you determine the amount of detected RAM without loading kickstart?
Edit 2: Looking at the clearly non-original EPROMs on the main board, I come to think that the hack on the piggyback is rather odd. What is in those EPROMs? Does the machine show a hand with "Workbench" or "Kickstart" upon power-on? If that is in fact a kickstart in those EPROMs that piggyback hack might be in order to use the WOM as RAM...)? However, that would only account for 256k, not 512k.... perhaps the second 256k of chip ram are falsely addressed in a fast RAM area... Odd... How much RAM does the machine show when you remove the front expansion?