I would actually prefer SMD versions LOL..

I'm actually thinking of using the bad pcb(s) to make a all in 1 rom replacement that will also support basic 4.0 on the 2001/2001N , you will need to socket the 74ls154 but will only need one rom board, no 74ls138 as mike pointed out you don't need it, the Pet only uses two of the CS lines.. and one of those can be converted to an address select line allowing 1 rom socket to replace 2 6540(s).