Recent appearances:
NGC Proof-66.  Ex - Superior Galleries "Pre-Long Beach" Elite Coin Auction, May 25-27, 2003, Lot 3035, sold for $5,175.00

NGC Proof-66.  Ex - Heritage Numismatic Auctions, Inc.'s "Philadelphia 2000 Signature Sale", August 6-7, 2000, Lot 6411, illustrated, sold for $4,485.00

NGC Proof-65.  Ex - Ira & Larry Goldberg Coin & Collectibles' "The Fairchild Family Trust Collection Sale", May 28-30, 2001, Lot 985, illustrated, sold for $4,025.00

Choice Brilliant Proof.  Ex- Stack's "The September Sale", September 12-13, 2000, Lot 726, sold for $1,150.00

Brilliant Proof.  Ex - Stack's "65th Anniversary Sale", October 17-19, 2000, Lot 1198, plated, sold for $891.25

NGC MS-67.  Ex - Superior Galleries "Pre-Long Beach" Elite Coin Auction, May 25-27, 2003, Lot 3036, sold for $7,475.00

NGC MS-67.  Ex- Heritage Numismatic Auctions, Inc.'s "October 2000 Long Beach Sale" October 5-7, 2000, Lot 8353, illustrated, sold for $4,140.00

PCGS MS-66.  Ex- Heritage Numismatic Auctions, Inc.'s "October 2000 Long Beach Sale" October 5-7, 2000, Lot 8352, not illustrated, sold for $402.50

NGC MS-66.  Ex - Heritage Numismatic Auctions, Inc.'s "Philadelphia 2000 Signature Sale", August 6-7, 2000, Lot 6316, not illustrated, sold for $368.00

PCGS MS-66.  Ex - Bowers & Merena Galleries' "The Rarities Sale", January 3, 2001, Lot 329, not illustrated, sold for $529.00

NGC MS-65, "Top 100."  Ex - Superior Galleries' "Pre-Long Beach Sale", October 1-3, 2000, Lot 3651, sold for $184.00

PCGS MS-65.  Ex- Heritage Numismatic Auctions, Inc.'s "October 2000 Long Beach Sale" October 5-7, 2000, Lot 8350, not illustrated, sold for $172.50

PCGS MS-65 DMPL.  Ex - Bowers & Merena Galleries' "The Cabinet of Lucien M. LaRiviere, Part II", March 15-17, 2001, Lot 494, unsold

Gem Brilliant Uncirculated.  Ex- Stack's "The September Sale", September 12-13, 2000, Lot 727, sold for $460.00

PCGS MS-64.  Deep Mirror Prooflike.  Ex- Heritage Numismatic Auctions, Inc.'s "October 2000 Long Beach Sale" October 5-7, 2000, Lot 8354, not illustrated, sold for $230.00

Notes:
The 1888 Morgan Silver Dollar is very common in Uncirculated and Gem conditions.  The most "common" Uncirculated grade is MS-64, followed by MS-63 and MS-65, in that order.  Prooflikes and Deep Mirror Prooflikes are scarce but easily obtained.  The finest examples certified by PCGS are 10 MS-67's, 6 MS-66 Prooflikes, and a single MS-67 Deep Mirror Prooflike.

With the exception of 1921, this date has the lowest number of surviving Proofs of any other in the series.  Nevertheless, the number of survivors is high enough that this date commands only a slight premium, if at all.  The finest Proof examples of this date graded by PCGS are a single PR-67, 6 PRCA-64 Proof Cameos, and a single PRDC-64 Proof Deep Cameos. 

Sources and/or recommended reading:
"The PCGS Population Report, October 2003" by The Professional Coin Grading Service