My first 486DX PC also only had 8MB of RAM until my parents through it out when I was a kid. I was personally shocked as well when I saw that this 486 PC had 64MB.
The 486 computer I had back in 1992 could support up 16 MB of memory IIRC. It was clocked at 25 MHz, but I did get the math-coprocessor and upgraded it to a DX4 75 Mhz. I knew of some models that could support up to 32 MB of RAM, but I wasn't aware of any that would support 64 MB of RAM (which was quite expensive at the time).
Yes. Some friends of mine once configured a 486 with 64 megs as a sort of practical joke, or cool thing to do. They temporarily cannibalised the other PCs at the school for memory SIMMs.
Having started in the 386 era, and having upgraded my AMD 386 from its original 2MB of RAM to the full 8MB, my first reaction on seeing that "64MB SDRAM SIMM-72" spec in this article was "wow, that's a lot of RAM!"