Rick,
I think the differential lock petal has been explained well but I doubt that you ever need it with the 4wd.
The knob under the seat that says <open-closed> as David said slows the descent of the implement on your 3ph. I leave mine open all of the time. When I first got my tractor mine was almost impossible to turn too. I got it to turn a little, put some oil on it and turned it back and forth till it got fairly easy to turn. I then turned it to the wide open position and left it.
I had an old IH444 that had very poor (worn out) hydraulics. When you were carrying an implement up in the transport mode, it took all of the hydraulics to hold it up and the power steering was starved to the point it was
very hard to steer. If I was going far, I would close off the valve after I got it raised. That way the hydraulic pump would be sending all of its flow to my steering.
I'm not sure if the
L3000 has a seperate pump for the steering but if it doesn't you might remember this tip. It'll probably be 40 or 50 years before you need it thought.
I'm also not positive about the arm rests but there were a couple on my dealer's lot when I bought mine and I'm pretty sure they didn't have them.
As far as the tractor not looking new most dealers subscribe to the "first in - first out" theory. I think that their inventory costs them more money the longer it stays on the lot. Naturally they want to keep the "lot time" down to a minimum. Also the pretty shiny one looks better to potential customers.
There was another thread about someone who picked out a specific tractor and the dealer was going to substitute it for another one that had been there for a while. The best thing to do (and I know it's too late now) is to write the serial number of the one that you want on the contract, on your check and anything else that passes between you and the dealer prior to delivery.
As someone else said tell the dealer you expect a can of can of Kubota orange and Kubota grey to go with your new toy (I mean tractor). You will get a lot of satisfaction out of going around taking care of little scuffs and rusty spots.
Also I wouldn't admit it anywhere else except on this board but I <font color=red>wax</font color=red> my tractor. After you get the touchups done, put you a good coat of the best automotive wax you can get on the sheet metal. A tractor is exposed to dirt, dust and mud much more than most automobiles so it just makes sense to protect it as much as you can.
Best of luck with your new tractor and I hope you enjoy it as much as I do mine.
TBone