Adco cover for 2720SD

[Craigrrr]

I have found an ADCO cover 22895 that is new in the box , I was told it has never been used or taken out of the box.. however the owner has had it for 3 yrs. in his garage. cost to me is 60 bucks is it still worth it, or do these things go bad just sitting in the box? I also spoke with ADCO and he thought I might need a 22852 cover since it goes up to 22 1/2 ' long whereas the 22895 is 18'
but I measured the closed TM and come up with 17' so I am thinking 22895 cover would be best fit, if they dont dry rot sitting in the box. Your thoughts are needed.