I agree that there is nothing on it to prove that it was sent on the first day of issue, and as has already been pointed out, it is not even likely a use in the first year of issue.
As for value, a very nice example of a #1 on cover with a PF certificate very recently sold on eBay
for #250 which seems about right in my opinion. It is not as nice because of its fold which detracts, but it is nicer in that it is dated which adds value so it is a wash in comparative values in my eyes. Here is a link to that auction: https://www.ebay.com/itm/Scott-1-18...047675.l2557