Yes, as long as the original purchase quantity was reasonable at the time for the federal election, following 2 CFR § 200.404. “A cost is reasonable if, in its nature and amount, it does not exceed that which would be incurred by a prudent person under the circumstances prevailing at the time the decision was made to incur the cost.” 

The direct cost allocation principles described in 2 CFR § 200.405 apply.  “If a cost benefits two or more projects or activities in proportions that can be determined without undue effort or cost, the cost must be allocated to the projects based on the proportional benefit. If a cost benefits two or more projects or activities in proportions that cannot be determined because of the interrelationship of the work involved, then … the costs may be allocated or transferred to benefitted projects on any reasonable documented basis.”

You should allocate the costs in proportions to the activities if the allocation can be determined without undue effort or cost.  If you can't determine the proportions because of the interrelationship of the work involved, you can allocate or transfer the costs on any reasonable basis.   The items you are talking about have specific uses that are only beneficial when holding an election during a public health emergency and probably would not be used during normal voting conditions.   It may be very difficult or impossible to determine cost allocation between the federal elections this year and hypothetical future needs that will be conditioned on the public health situation next year.  In such a case, the cost can be allocated to the grant on a reasonably documented basis, and the items can be used as needed in future non-federal elections. However, if allocation between federal and non-federal elections can be determined without undue effort or cost, it must be done (e.g., purchase of ballot printing equipment to handle a need for increased demand of mail ballots would likely have determinable benefits to future non-federal elections).