Here is THE list with many above and below yours. I have owned many Spencer's over the years and currently have 3 one of which is a direct match. One thing I can tell you is "If it ain't on the list, It ain't on the list" They did NOT come from the factory in order of serial # plus these were transferred from unit to unit such as one of the ones I own being transferred to Gen Croxton. If you look at the issue for the 7th Penn Cav you will see that are NOT in order.
1392260C 05 64CO I 3RD MICH VOL CAV
1392560C 65CO D 6TH ILL VOL CAV
1393560C 05 64CO I 3RD MICH VOL CAV
1393660C 042264CO D 5TH NY VOL CAV
1395460C 042264CO D 5TH NY VOL CAV
1396760C 05 64CO I 3RD MICH VOL CAV
1397160C 111464CO K 11TH MICH VOL CAV
1402660C 02 65CO E 7TH PENNA VOL CAV
1404660C 05 64CO I 3RD MICH VOL CAV
1405060C 65CO G 8TH NY VOL CAV
1406360C 02 65CO E 7TH PENNA VOL CAV
1406760C 02 65CO E 7TH PENNA VOL CAV
1407460C 02 65CO E 7TH PENNA VOL CAV
1409760C 05 64CO I 3RD MICH VOL CAV
1412060C 02 65CO E 7TH PENNA VOL CAV
1413160C 013167SA (REPAIRED)
14147 C 072773TONKAWA SCOUTS FT GRIFFIN
1416660C 65CO D 6TH ILL VOL CAV
1417560C 10 64CO I 19TH NY VOL CAV
1420360C 02 65CO E 7TH PENNA VOL CAV
1421460C 02 65CO E 7TH PENNA VOL CAV
1422560C 64CO B 2ND MICH VOL CAV
1423460C 02 65CO E 7TH PENNA VOL CAV
1423860C 02 65CO E 7TH PENNA VOL CAV
14238 C 072773TONKAWA SCOUTS FT GRIFFIN
1425060C 02 65CO E 7TH PENNA VOL CAV
1425460C 02 65CO E 7TH PENNA VOL CAV
1426360C 02 65CO E 7TH PENNA VOL CAV
1426960C 02 65CO E 7TH PENNA VOL CAV
1427960C 02 65CO E 7TH PENNA VOL CAV
1428360C 02 65CO E 7TH PENNA VOL CAV
1428460C 02 65CO E 7TH PENNA VOL CAV
1430260C 02 65CO E 7TH PENNA VOL CAV
1434760C 02 65CO E 7TH PENNA VOL CAV
1434860C 02 65CO E 7TH PENNA VOL CAV
1435460C 09 64CO E 19TH NY VOL CAV
1437260C 02 65CO E 7TH PENNA VOL CAV
1437960C 02 65CO E 7TH PENNA VOL CAV
1438160C 02 65CO E 7TH PENNA VOL CAV
1439260C 02 65CO E 7TH PENNA VOL CAV
1439960C 02 65CO E 7TH PENNA VOL CAV
1440460C 02 65CO E 7TH PENNA VOL CAV
1446960C 65CO D 6TH ILL VOL CAV
1447460C 02 65CO E 7TH PENNA VOL CAV
1447860C 02 65CO E 7TH PENNA VOL CAV
1450860C 02 65CO E 7TH PENNA VOL CAV
1452460C 02 65CO E 7TH PENNA VOL CAV