ACR WDB ALTDEV OVERSHOT DURING GS INTERCEPT AT ANC BECAUSE THEIR ALT WAS SET INCORRECTLY. THEY WERE 1000 FT LOW XING THE OM.

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WE HAD MADE A NORMAL DSCNT TO ANCHORAGE FOR AN ILS 6R APCH. ANC WAS RPTING A 2300 CEILING AND 1 1/2 MI VISIBILITY. OUR NORMAL CHKLISTS WERE COMPLETED AND THE APCH WAS BRIEFED. I WAS FLYING. WE JOINED THE LOC WHILE DSNDING TO 2000 FT ABOUT 10-12 MI FROM THE MARKER. I HAD ON AND OFF FLAGS ON MY GS NEEDLES EARLY ON THE APCH (NOT TOO UNUSUAL) AS WE APCHED THE OM WE HAD FULL UP NEEDLE DEFLECTION ON ALL 4 GS INDICATORS. THERE HAD BEEN A CALL FROM THE TWR TO 'VASI PICKUP' AS TO WHETHER HE WAS CLR OF THE RWY OR NOT. THIS LED US TO CONSIDER WHETHER THE PICKUP WAS CAUSING OUR PROBLEM. ABOUT THIS TIME WE CROSSED THE OM (BLUE LIGHTS; ADF NEEDLE SWING). GS NEEDLES WERE STILL FULL UP; INDICATING WE WERE BELOW THE GS. BECAUSE OF THIS AND THE FACT WE WERE AT 2000 FT; I TURNED AND TOLD THE FO TO ADVISE THE TWR WE WERE GOING AROUND. AS I SPOKE; HE WAS SAYING 'RWY IN SIGHT.' I HAD BEEN BASICALLY INST FLYING (NOT LOOKING OUT MUCH). I LOOKED OUT AND SAW THE RWY AS WELL AS THE ENTIRE ARPT. INFLT VISIBILITY MUST HAVE BEEN 4-5 MI. WE INDICATED HIGH ON THE VASI AND HIGH ON THE GS NEEDLES AT THIS POINT. WE MADE AN UNEVENTFUL LNDG FROM THAT POS. AFTER LNDG WE QUESTIONED GND CTL AS TO THE POS OF THE PICKUP DURING OUR APCH AND IF ANYONE ELSE HAD RPTED A GS PROBLEM. GND CTLR REPLIED THE PICKUP WAS CLR AND NO ONE ELSE RPTED A GS PROBLEM. WE ASKED MAINT TO CHK THE GS; BUT I THOUGHT IT WAS STILL POSSIBLE THE 'VASI PICKUP' HAD CAUSED THE PROBLEM. ALMOST 12 HRS LATER; AT HOME; I RECEIVED A CALL FROM THE OUTBOUND CAPT OF MY ACFT WHO STATED HIS FO HAD FOUND THE ALTIMETERS SET 1000 FT ABOVE ARPT ALT. MAINT HAD BEEN IN THE ACFT BUT THERE WAS NO REASON TO BELIEVE THAT THEY HAD CHANGED THE ALTIMETERS. UPON REFLECTION; THIS INCORRECT SETTING WOULD COINCIDE WITH AND EXPLAIN OUR APCH EXPERIENCE. IT APPEARS THAT THE ALTIMETERS WERE SET 1 INCH HIGH. 29.86 INSTEAD OF 28.86. TO SAY THE VERY LEAST; THIS WAS A VERY SOBERING EXPERIENCE. I CONSIDER MYSELF TO BE A VERY CAREFUL PLT AND HAVE NOT HAD AN INCIDENT NOR A VIOLATION IN 30 YRS OF FLYING. THERE ARE SEVERAL ASPECTS TO THIS 'HAPPENING' AND I NOTE THE FOLLOWING: THE OUTBOUND CAPT LISTENED TO THE ATIS AND NO MENTION OF 'LOW' ALTIMETERS WAS MADE. IF APCH ADVISED OF 'LOW' ALTIMETERS NEITHER THE FO NOR I WERE AWARE OF IT. THE POSITIONING OF THE ATIS INFO AFTER IT IS HANDED UP FROM THE SO PRECLUDES HIM FROM SEEING IT! POSSIBLY LOSING ANOTHER CHANCE TO CATCH THE ERROR. SOME INFO MAY LEAD YOU TO AN INCORRECT ANALYSIS OF THE PROBLEM (IE; GS PROBLEM CAUSED BY THE PICKUP TRUCK). FATIGUE MAY HAVE CONTRIBUTED TO THIS PROBLEM -- THIS WAS AN ALL NIGHT FLT FROM JAPAN. RECOMMENDATIONS: LOW ALTIMETER SETTINGS SHOULD ALWAYS BE MENTIONED BY ALL PARTIES INVOLVED; USING THE WORD 'LOW'. X-CHKING ATIS SETTING WITH A SECOND SOURCE IS A MUST! ALWAYS. THE SO MUST HAVE OR BE ABLE TO SEE THE GIVEN ALTIMETER SETTING.