For future reference if you want to know how old a tire is, there is a date code on one side of the tire right after the DOT#.
It will be a 3 or 4 digit number. Everything manufactured after 2000 went to the 4 digit number, prior to that was a 3 digit number.
The first 2 digits are the week of the year (01-52) and the second 2 digits are the year (00-13) currently.
So if you find tires that look good but are date coded older than about 7 years, it'd be a good idea to plan on replacing them due to the age if you plan on regular usage.
Last but not least

if you find any that are 3 digit codes, please don't chance doing damage to your car or boat by running them across the desert in the summer
