Potential 360 build couple of questions

Hey there guys,

I have a guy offerring me a 360 out of a 91 ramcharger for a really good price complete and running. I figure i mine as well pick it up, but i have a few questions.

He said its not a magnum, and i did a google search, but im not 100% sure...some say the 5.9 was not magnum until 92 some 93...im just looking for a hard number

Second, in regards to the year of block, are there any casting weaknesses by going with this year of motor, especially in terms of wall thickness or core shift.

Last, i was kinda hoping to try and reuse the bottom end if possible (I believe its external balance?) but im not sure what they are like in that year? im assuming cast crank, rods and pistons? whats the compression like?

any help with this stuff would be greatly appreciated!

Thanks!
Matthew