[ROVERNET - UK] 3500s head compatibility

[peter king]

Hi all.

I'm gathering parts to rebuild my '70 3500s engine, and I need to  
replace damaged heads. I saw two on ebay with casting numbers 581829  
and 1358219. My heads both have the casting number 602924. Can anyone  
tell me whether the numbers on the ebay heads are compatible, or if,  
with their different numbers, they are indeed a matched pair?

Thanks,

Peter