Hi, I'm glad to hear that you're composing a Eureka models & spec's timeline. It's hard to locate information on all the models. I've recently come across some model lists on vacuum parts websites, so thought I'd pass them on to you in case you need them or just want a cross-reference. Incidentally, the letters after the model numbers are the "Type"s as found on the manufacturer's labels. The lists may not be completely accurate, though; for example the 1475A had been omitted. There is also a photo of a 1910-1958 Eureka model and serial number list on another thread.
F&G Bag Uprights (1958- )
238AK, 259, 260, 267(Cord-A-Way), 270 (Vanguard)
1401A/B/D; 1402A/D; 1403A; 1404A/B; 1405A; 1406A/B/D/E/G/H/J/K; 1407B/D; 1408A; 1409A/B; 1410A/D; 1411A; 1412A/B/D; 1413A/B; 1414A/B; 1415A/AG/B/BG; 1416A/AS/B/BS/D; 1417A/B;
1418A/B; 1419A/B; 1420A; 1421A; 1422A; 1423A/B; 1424A/B/D/E/F/G; 1425A/B/D/E/F/G; 1426A/B; 1427A/B/D/E; 1428A/B/D; 1429A/D; 1431A/B/D; 1432A/B/D/E/F; 1435A/B/D; 1436A; 1437A; 1438A; 1439A; 1440A; 1441A; 1442A/B/D; 1443A/B/D; 1444A; 1446A/B; 1447A; 1448A/B/D; 1450A; 1452A/B/F; 1453A/B/D; 1454A; 1455A; 1456A; 1457A/B; 1458A/B/D/E/F; 1459A; 1462A; 1463A; 1466A; 1469A; 1470A/D; 1471A/B; 1473A/B;
1475A (75th anniversary); 1485A/B/D; 1486A; 1489A/AM/B/BM; 1490A; 1495A
1903A/B, 1923A/B, 1925A/AT, 1928A/AT, 1931A, 1932A, 1934A/A1, 1935AT/B/BT, 1941E,1942A/B, 1943A/AT, 1945B, 1946A, 1947A, 1967A/AT/B/BT, 1968A
2008A,2009A,2010A/AT/BH/BHT/BT/R/RB/RY/RYT, 2011A/B, 2012A/AT/B, 2013AM/BM, 2014A/B, 2015A/B, 2016A, 2017A, 2018A, 2019A/AT, 2020A/B/BT/R/RB/RR/WT, 2021BT, 2022A/AT, 2023A/AT, 2024A, 2025A/B/BT, 2026A, 2027A/AM, 2028A/B, 2030ADV, 2033A, 2035A, 2036A/B, 2042A/B/D/ DT/E, 2043A, 2044R/RB/RG, 2045A, 2047A, 2048A/B, 2049A, 2050A/B/R/RB, 2052A, 2053A, 2055A/AP/B/BP, 2058A/AT/B/BT/D/DT, 2060R/RB, 2061A/AT/B/BT/D/DT, 2062A/B/D, 2064A/B, 2068A/AY/BYT, 2070A/B/D/E/F, 2071A/B/D, 2072A, 2073A, 2074A, 2076A, 2077A, 2079A, 2080A/B, 2081A/B, 2082A,2083A, 2084A, 2085A, 2086A/B/D, 2087A, 2088A, 2090A, 2091A/B/D/DT, 2092A, 2093A, C2094, 2095A, 2097A, 2101, 2105, 2107, 2109, 2118, 2122, 2124, 2125, 2134, 2150, 2152
4036, 4040, 4053, 4060
5071D, 5071E
6484A, 6484AT
7534A, 7575
Sanitaires - Blue Line SC679, SC684, SC684E, SC689, SC886, SC887, SC887A, SC888, SC899, S634, and S647
Sanitaires - Red Line
SC684F-2, SC684F-3, SC689A-2, SC689A-3, SC886E, SC886E-1, SC886E-2, SC886E-3, SC887B-2, SC887B-3