Our street was renovated and the gutters replaced. This work required digging up 2-4 feet of lawn on either side of the street, which was reseeded. As a result of the digging, the permanent surveyor's pins on all our lots were removed. Surveying is expensive. Do we have to pay to have all our lots resurveyed? It just doesn't seem right.

Who moved them? Typically it is illegal to move the pins. Whomever moved them should replace them. They are really a reference point for you since almost all property is resurveyed prior to a closing. I wouldn't pay to resurvey.

The town resurfaced the road and replaced the gutters. Whatever company they hired to do the gutters, dug up the pins. I would have to go to the town to ask if they would replace the pins - just want to know if I have a leg to stand on here...

I worked for a different state as a highway construction supervisor. If we had received a complaint of this description we would have required the contracor's survey party to restore those markers (assuming that the project specifications supported that instruction and if we did not have authority to direct the contractor to do so, we would have restored the markers with our own state survey parties). Just one proviso-budget problems were not nearly so severe when I was in that position. You can probably research the DOT (or applicable county or municipality) specifications online and possibly find a reference in those specifications as to the contractor's responsibility per the contract. Generally, conditions are to be "replaced in kind-same as before-or as good or better than it was before the work was started. Being armed with some quotes from their own specifications (even if you don't have to use them) is good preparation. Contact a highway division government employee, preferably in writing--do not go directly through the contractor or a consulting engineer (if possible).
Go over that rep's head if necessary but give them an opportunity to respond first--and request a written response. What they did was definitely improper (possibly not intentionally) but budgets are tight and it is impossible to predict how they will respond.
Best wishes.

Whoever did the work, did replace our mailboxes and reseed the lawn, so I suppose replacing the pins might reasonably be expected. We may have to prove somehow that the pins were there; not sure how to do that.

Are the other limits of the properties marked? Even if not, still worth a try. Maybe some of the documents/plats on file with the last transfer of deed show them or refer to them.