The mower is nothing special, you can look at another one the same in this thread:
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=34536

The Lawn Boy engine was popular in the US back in its day. I haven't heard of anyone getting excited about them because of extraordinary operational performance, the way they sometimes do about Japanese 2 strokes. That mower is obviously pig-ugly, and I see no reason why it would be more valuable than other roadside pickups. However, if you want to try you could always put it on ebay, preferably with a bag over it so nobody gets ill.

Masport fitted some earlier D series Iron Horse engines (the ones with the "hammerhead" top cover) and those made nice looking mowers, that could be worth collecting.