Cut them in half and count the rings, of course. Seriously, twenty years of development and activity will inevitably result in obvious signs of wear and tear. Brand new would exhibit no scuffs, no scratches, no dents, no dings, no callouses, no scars, no wear and tear, no aging effects inside or out.
SBC theologians say that people such as Ken Ham are presuppositionalists. RCC militants such as Matt Walsh consider people like Ken Ham as protestant heretics who dispute scientific deep time falsely.
When Ken Ham classified Walsh's theology, Walsh demanded an apology for a personal attack. Ham responded with it was not a personal attack but a standard historic theological statement and offered Walsh an all- expense-paid trip to the Ark Encounter and the Creation Museum. Walsh never acknowledged the offer.
Walsh does not understand creationism and attributes doctrines to it that creationists do not believe. In the case of Dr. Norman Geisler and Dr. Richard Land, they just cling to the evolutionary scientific thinking of their college days.
I am blessed because I live very close to the Creation Museum and Ark Encounter could go there and back in one day.
I had a friend who had gone to the Ark Encounter with his wife before I went on a senior tour there. He said that he didn't believe that there were dinosaurs on Noah's Ark. I confessed that I wasn't an expert.
Ken Ham built the Ark 510 feet long, 85 feet wide, and 51 feet high (7 stories high). He used the royal cubit of about 20 1/2 inches. Amish construction crews did most of the carpentry work.