Here are some catalog abbreviations that will probably be imprinted on the bottom of a piece. From a Lodge price list dated Jan. 1, 1986. For most of the 1980's and 90's if not earlier Lodge made pans with an incised catalog abbreviation on the bottom such as:
SK skillet, SC skillet cover, CS chef skillet, SQ square skillet, DO dutch oven, CF chicken fryer, FF french fryer w/basket, SP sauce pan and/or stew pan, NG round griddle-new style, OG round griddle-old style, BE bacon & egg skillet, TB top of stove broiler (Axford style skillet), DOT dutch oven trivet, DOF deep fry oven w/cover & basket, CO camp oven, IC iron cover fits chicken fryer and dutch oven, GC glass cover, CC indoor/outdoor combo cooker, CK country kettle, FBK flat bottom straight kettle, RBK round bottom straight kettle, TK tea kettle, OS oval serving griddle, LG oblong (long) griddle, NTP no trump card pan, M muffin pan (6cup turk head), C cornstick pan, P popover pan, B breadstick pan, CB corn bread skillet, CP fluted cake pan (bundt pan), FB french bread (2-loaf vienna roll loaf pan), D danish cake pan, AT skille ash tray, FB fish pan, CAF camp fryer.
Lodge's full catalog number would be, for instance, 5SK1 for a No. 5 skillet, polished finish and 5SK2 for natural finish. You will see the 5 and the SK on the bottom of the skillet but not the whole catalog number I don't think. Anyway, when you see abbreviations such as above you can almost bet that it is a Lodge pan from the c.1970-90's period. Could be earlier, too. I think Lodge began to put their new LODGE logo on the bottom of pieces sometime in the later 1990's but not sure. Many items have been discontinued since my price list and some new items added. I'm not sure if Lodge is making their polished pieces any more. Also in my price list are 8 different trivets, sets, various covers, display racks. A very full line back in 1986.
Steve