Pairs MFG CO No 5

This is a childsfolding  chair , made by the Pairs MFG Co in South Pairs ME . Seems HARD to find much info on the company . I've seen other pieces online , but have NEVER seen this chair . Trying to find out when it might have been made , and possible value . The chair is a folding one . Is VERY sturdy . Looks like a repair was made , and there is a small crack , see picture , but does not effect the chair . It is strong , and was well put together . I've noticed too , this company had NUMBERS on there pieces . This has a NO 5 . I'd like to know what that means too . Thank-you for your time , and what ever info you can provide !