NO DO NOT BUY THAT KIT!!!!
It has no value except maybe to collectors who like scarce things.
This has been discussed in the past here. It was a particular bone in the craw of our late friend Dr. Tilley. Any giggle search using the terms "Revell Seeadler", "Finescale Forums", "Need advice on painting plastic sailing ship deck" and a few others will give you all the info you need, so I won't repeat it here in any detail.
Revell sold the USCGC Eagle kit starting in 1958. It's a good kit, although it isn't accurate for a whole different set of reasons that are actually interesting.
In 1960 Revell pulled a marketing scam and reissued the kit as the Gorch Fock and as the Seeadler. The GF is a little closer, but the Seeadler is completely bogus. Revell removed the motor launches, replaced them with open boats, and replaced the mizzen mast with a square rigged one to change her from a bark to a full rigged ship.
There was even a note in the box from Count Von Luckner himself.
Sorry, it caused me pain as well when I was a kid reading his biography. For quite a while this was, however fake, about the only WW1 plastic ship model around.
Bill