I'm also thinking out loud, and I have no direct experience with this but do think this would fall under the category of involuntary conversions that includes seizures. When the IRS sells the property to satisfy the debt, if it ends up with excess proceeds, those funds are returned to the taxpayer. Doubtful that would ever happen, but it does seem that this would be reported as a sale.
Also to consider when reporting this is that the IRS tallies up all costs associated with the seizure including costs to remove and sell the property, and if the sale does not go through or property is returned to the taxpayer, those costs incurred by the IRS are added to the balance owed to the IRS by the taxpayer. With that in mind, I would think that those costs incurred would be considered additional expenses of "sale" that would reduce any resulting gain from the transactions.
Lastly, if any personal property was seized and sold, remember that a loss from the sale of personal property isn't deductible, but any resulting gains would be taxable.