i got this version 1840, but there are rumors about version 2040. but i think it's the 1840 as there's no timebomb and no watermark and version number written near service pack 1 (the window where u got your pc indice) winver just says it's build 6001.18000 nothing about 1840 or other thing like that. but if it was a rc build MS would insert a timebomb and a watermark. now i'm not sure 100% it's the RTM. and it's not a .exe from MS but a .img called 6001_18000_X86_FRE_LONGHORN_RTM_080118_1840_WAVE0.IMG with a size of 440MB. there a loader in it so it seems the loader still works with sp1.
thought its possible that will be actual RTM (1840)..it will only be for sure certain when its 'Officially Released' by Microsoft....as for the wave0 and the wave1...wave0 contains 5 languages...and the wave1 contains 36 languages..thus the big differance's in size. 36 language version: 6001.18000.080118-1840_iso_client_sp_wave1-FRMCSP1_DVD.iso As well as full, slipstreamed (Ultimate, Home, Home Premium) versions: 6001.18000.080118-1840_x86fre_Client_en-us-FRMCFRE_EN_DVD.iso 6001.18000.080118-1840_amd64fre_Client_en-us-FRMCXFRE_EN_DVD.iso Business: 6001.18000.080118-1840_x86fre_Business_en-us_VL-FRMBVOL_EN_DVD.iso Enterprise: 6001.18000.080118-1840_x86fre_Enterprise_en-us_VL-FRMEVOL_EN_DVD.iso And Windows Server 2008: 6001.18000.080118-1840_x86fre_Server_en-us_VL-KRMSVOL_EN_DVD.iso