Charles - bibliofind (on the web) lists the following copies.
Dave Thomson

Twain, Mark. ( With drawings by John Groth ).: The WAR PRAYER. ; [NY].: St.
Crispin Pr., [1968].. A Very Good reading copy., Hardcover. Cloth spine,
paper on boards. Unpaginated. Illustrated throughout., Literature Mark Twain
Civil War  (UR#:BOOK007914I)  Offered for sale by Larry Tucker Books at
US$25.00

Twain, Mark: The War Prayer ; A St. Crispin Press Book/ Harper & Row, No
place, 1923 & 1951. First thus. Illustrated by John Groth. Very good. Clean,
tight, unmarked save for owner's embossed mark on front free endpaper. In
fair dj. Front
panel has several closed tears at upper edge and one 1" closed tear at lower
edge. Rear panel has 1" closed tear at upper edge. Edgewear. Rubbing.
(mt-42)   Offered for sale by The Wayward Bookman at US$32.00


TWAIN,Mark : The War Prayer. ; TWAIN, Mark. The War Prayer. Illus. by John
Groth. Thin 8vo, d.w. N.Y.: St. Crispin Press, (1968). Fine. A classic of
anti-war literature, Twain wanted it printed only after his death, as "only
dead men can tell the truth in this world". Appearing originally in "Europe
&
Elsewhere", this is the first separate printing, and is illustrated by war
correspondent-illustrator John Groth. Presentation copy from Groth, with a
powerful ink drawing covering the front flyleaf and part of the front
endpaper.
F.E. (UR#:G98358 ) Offered for sale by Argosy Book Store at US$300.00


Twain, Mark: The War Prayer ; Harper and Row, 1968. Good ++ Hardcover in
Good + Dustjacket. A parable whose irony and satiric thrust make it a minor
classic of anti-war literature. This edition includes drawings in a second
color by John Groth which, like the parable itself, have a universiality of
theme and design beyond time and place. Foxing on edges, DJ faded and
chipped at corners. 1/2” piece of DJ missing from lower spine. 1st
illustrated edition. Owner inscription-front free end
paper. Rare Room First Edition's.   Offered for sale by Ithaca Books at
US$60.00