Might be pretty good. Is the owner wanting you to reimburse them the maintenance fees on those 30 UY2001 points, or on the full 150 2002 year points?
Figure your closing costs would be about 3.00/point which puts it at $10 less than Disney right now. If Disney sold you an August UY today you'd get the full 150 2002 points but would be paying a pro-rated maintenance fee on them for the rest of 2002, or basically 1 to 2 months. At about $4.50/point that's be around $100. The seller has paid 12 months for those points (He paid it all last January, or about $675. If he's asking you to reimburse that money then the value to you is about $575 less than going through Disney, or about $3.80/point making your costs about $73.80 compared to Disney's $80 (but $84 in less than a month)
However the banked 30 points have value also. If you just figure the dues of about $4.50, then that's about $0.90 on the 150 point purchase making your final costs about $72.90/point.
If the seller is not asking for any reimbursement at all then your comparison is $70/point compared to Disney's approximate $80.67/point including the pro-rated dues you'd have to pay.
Plus you'd get the other 30 points totally free.
Anyhow, just some additional thoughts. If the seller is not asking for any reimbursement of dues, then you'd be saving about $1500 compared to Disney.