It is fairly simple to check the timing, there are marks on the crank pulley and inside the pump behind a little timing mark cover. Timing is set by removing the front cover of the pump drive and loosening bolts that hold the drive gear to the pump drive hub. The holes are slotted, allowing you to adjust the timing as required.
If you want to try it yourself, get hold of the tech info first, if you don't have access to a shop manual I think I have a electronic version of a manual that would show how to do this, I might be able to send you the pages you need if you would like as long as you don't need it for a few days.
I have nothing against used parts, but only in certain places. Utilizing replacement used parts in an engine rebuild will almost always come back and bite you where and when you don't need it too. I warranty any work I do, but only if the important parts are replaced with new, reman, or repaired, eg: bearings, clutch discs, shift syncros, liners, pistons, ect. I will put in used parts if they are insisted on, but then there is no warranty. I will not even work on something if I know it needs new and the customer says no way. They can take it somewhere else.
Knock on wood, I haven't had one come back yet, but its inevitably gonna happen someday...but maybe thats some proof of there is a time and a place for used parts. I might be slow, so I'm told, but its because I spend more time in the field than the shop, but my customers appreciate the meticulous nature of my work. That and I'm half the price of the guys in town