20 First Day Issue Covers, '86-'90 gold replica cachet 
by Postal Commemorative Society, now known as PCS Stamps & Coins. 

Subjects of the covers and stamps are:
The Moore and Sitting Bull covers come with a separate card listing date, First Day city, stamp designer, and details of why the subject is honored with a stamp. The other envelope is not accompanied by a similar card.
  • Executive Branch Constitution Series Apr 1989
  • Letter Carriers We Deliver, Aug 1989
  • The White House, May 1986
The Letter Carriers and White House covers come with a separate card listing date, First Day city, stamp designer, and details of why the subject is honored with a stamp. The other envelope is not accompanied by a similar card.
  • US Constitution Aug 28 1987
  • Bicentennial of US House of Reps, April 4 1989
  • Bicentennial of US Senate, April 4 1989
The House of Reps cover comes with a separate card listing date, First Day city, stamp designer, and details of why the subject is honored with a stamp. The other two envelopes are not accompanied by similar cards.
  • Washington 100th Anniv, Feb 22 1989
  • South Dakota 100th Anniv, May 3 1989
  • Idaho 100th Anniv, Jan 6 1990
Each cover comes with a separate card listing date, First Day city, stamp designer, and details of why the subject is honored with a stamp.
  • Montana 100th Anniv, Jan 15 1989
  • North Dakota 100th Anniv, Feb 21 1989
  • Rhode Island 200th Anniv, May 29 1990
Each cover comes with a separate card listing date, First Day city, stamp designer, and details of why the subject is honored with a stamp.

Antarctic Explorers:
  • Nathaniel Palmer
  • Richard E. Byrd
  • Lincoln Ellsworth
Each cover comes with a separate card listing date, First Day city, stamp designer, and a description of why the subject is honored with a stamp.
Olympic Games (Both Minneapolis July 6, 1990)
The Swimming cover comes with a separate card listing date, First Day city, stamp designer, and details of why the subject is honored with a stamp. The other envelope is not accompanied by a similar card.

All 20 are in 3-part protective plastic pages. 
Condition appears to be good -- the protective pages are scuffed with light soil -- there doesn't appear to be soil on the envelopes themselves; I'm selling several such pages, and I don't wish to possibly damage the envelopes by removing then replacing them.