This appears to be a DVD of the Marciano-Roland LaStarza fight, but it doesn't seem to be available from NetFlix:

http://www.imdb.com/title/tt0372403/

Here are two more with Marciano that NetFlix doesn't seem to have either:

http://www.cduniverse.com/productinfo.asp?pid=7055005&style=movie&cart=368627099&BAB=C

http://www.screenselect.co.uk/visitor/product/28133-Rocky-Marciano-Vs-Joe-Walcott.html