AFAIR Apple sold a 2 MB upgrade kit through the dealers. For 4 MB you had to by two kits.

I priced the Apple kits in 1987 and orderd 3rd party memory as it was significantly cheaper than Apples. I went from 1 MB to 4 MB and thought I would never need any more memory than that.

At the time I was with Continetal Bank in Chicago and our Burroughs minni computer that had a staff of 5 to run was maxed out at 2 MB RAM!