buying a 405

My son, the college student, saw an '89 405 MI 16 for sale in Indianapolis for $2,000.00. The Kelly Blue Book price lists $1,200.00 as a more reasonable price for that year, with 73,000 miles and in good condition, being sold by a private party. What should he look for in a 405, as far as problems? Rust? Oil consumption? Bad transmission? I guess what I'm asking is, what are common problems with an '89 405?