Actually if they were purchased by someone else they are not really yours unless they gave them to you to which I would have paper work that says so, also since they were once installed so their value is not going to be the same if they came right out of the box unless maybe they never was installed in the first place, personally I would never take the old fixtures as part of the payment since it is almost impossible to find a new home for them which could take years to do, custom types are even harder since not everyone will like the same style, and as far as the lean or claim against the job, I would not reduce the claim amount just because they given you these old fixtures, I would gladly give them back if they tried to use them to get money off the bill, maybe something more common that we used allot of, but custom pole light heads that might be only designed for the poles used would not be an easy item to reuse somewhere else, and the fact that if your state has a state wide dark sky law or light trespass law you might not be able to use them anywhere else legally so they could end up worthless or maybe sell them on E-bay?
Here its not more then 3% of light can not trespass onto adjoining property.
Here we also have the small claims court we can go after amounts lower then $5k so if a home owner fails to pay for a repair or a small job then we can take them to small claims.
Here the court systems treat the person who untimely received the work and or materials that became part of their property as a gain to be the final person who is responsible to the paying of the bill, even if they had paid the GC already, it is up to them to go after the GC to get their money back.
We had a GC who was paid in full by most of the homeowners to build there houses, the GC had most of the houses about 80% complete when he skipped country without paying anyone including the lumber yards, the homeowners ended up having to pay all the bills that the GC didn't including all the contractors and lumber yards, the owner had to almost pay for the building of the houses twice, he skipped country with over $4 million, they think he went to south America somewhere, but if he ever returns he is facing all the charges and sentencing he was found guilty of because his trial continued even without his presence he was also hit with tax evasion, his poor dad also lost all his houses and properties since he had put up them to back the finance of his sons company, I really felt sorry for these homeowners and his dad, but they should have not paid him before the house was complete.