Yes, the last digit of an ISSN does seem to be a check digit.  If you search an
ISSN on OCLC but get the last digit wrong, you'll pull up the record you want
anyway.  I found that interesting when I noticed it a while ago.  It may be
more commonly known than I realize, I suppose.

_______________________________________________________________________
/ Pete Wilson                        /            Bitnet:             /
/ Serials Librarian                  /      WILSONJP@VUCTRVAX         /
/ General Technical Services         /           Internet:            /
/ Vanderbilt University              / wilsonjp@ctrvax.Vanderbilt.Edu /
/ Nashville, Tennessee 37240         /      Phone: (615) 322 - 2409   /
-----------------------------------------------------------------------