Rick the JD 530 baler would be no newer than a 1989 model The 535s came out in 1990. This is from memory but it will be within a year either way. The JD 530 baler was a good baler but it was twine only. That holds the value down. Also the condition of the belts and splices is just as important as the pickup. A new set of belts can cost you 2-3K depending on what type you get. Also the condition of the rolls and bearings should be checked.
I just remembered. Look at the sprockets and drive chains on the baler. If the sprockets are worn to points then they will need replaced down the road. All the sprockets and chains will run in the $1000-1500 range.
The rake being a Vermeer still make it kind of a wild guess because they make several type as well.
The mower is more than likely a arm type of disk mower. So that would be fine in grass type hay but not the best if you have clover or alfalfa. They need conditioned.
So If we put the baler at $3500-4000
The rake at $2000-2500
the mower at $2500-3000
So that would but you in the $8000-9500 for the package. So the $9000 asking price is in the market but not a real steal unless something is way more valuable than we can tell from the limited information.
So if you need/want a complete set of hay equipment then it may be a good deal. Just remember that livestock equipment is going to be cheaper in the next few months or years. The high feed costs are really pushing down the value of any of the livestock equipment. I have not even traded in a baler for the last year or so because of this. I have seen real good JD 566 round balers with mesh not break 10K. The cheaper stuff is holding up a little better but even it is sliding. I am seeing dolly wheel NH bar rakes not break $1000. They where bringing $1500-2500 just a few years ago.
So look all of the stuff over to see its actual condition. Also don't blindly take the sellers word on the age/value of the equipment. They already have it five years newer than it could be. That "total rebuild" it a real vague term too. They could just have put pickup teeth in the pickup and called that a total rebuild. Try to get them to give you a copy of the work order.
The reason I am wanting you to be real cautious it that good hay tools can be found worth the money right now. The market is real soft. The package they are offering is a fair amount of money to be spending and not getting pretty high quality equipment. $9000 will go a long ways right now and over the winter toward hay equipment.
I am not saying the package is not good but it is in the higher end of the range. So it needs to all be in good shape.
I wish I could see some pictures and models/brands/serial numbers to be able to give you a better appraisal.