Welcome Francisco! You may find some help here, but the majority of us are 95-99 model year owners. A couple guys do also own older Rivs.
For interior parts for 68/69 Rivieras, your best bet is to ask on www.v8buick.com in the Parts Wanted section, or also check out the Riviera Owners Assoc forums on the AACA website. You aren't going to find interior parts at the common national suppliers, like a Jegs or Summit, and there are few to none reproduced.