Both 68 and 69 had space saver tire option RPO 65.
The 68 AIM does not have any work instructions but your 69 AIM has them on UPC N65 A1 page 407. 69 floor pan is different than 68.The brackets where installed by Fisher so they are not in the AIM.
I do not know if bracket for the floor is different between std. tire, space saver.68 and 69, but the floor bracket is available after market.
Maybe someone has a picture they will share.
Bob