It amazes me that manuals of old sets do not have a list of the parts needed instead of "spot the differences" and good luck. not even highlighting the new parts. :
Where to post MOC instructions for Alternate Builds of old Lego sets? : r/ lego
Old LEGO® Instructions | Vintage lego, Lego, Lego house
LEGO® Classic toys - Free building instructions | Official LEGO® Shop US
Old Instructions - Your online source of Lego instructions, catalogues and ideas books from years pastOld Instructions | Your online source of Lego instructions, catalogues and ideas books from years past
history - What did Lego set instruction manuals look like in the past? - Bricks