Given that it also has an 8*8GB variant (which cannot be the total capacity because 1GB DDR4 DIMMs are not a thing)… yeah, I’m sure that’s what the listing means. Again, no comment on how legit it actually is, I have no experience with buying server parts on eBay.

the only available option is 64gb

I’m not saying it looks legit, but the listing definitely has 8*64GB modules - 512GB in total.