I use Doyle's book mainly for the photos, and brief descriptions. I also have the TCA Standard of the World book, along with Greenberg's Guide to Prewar Vol II, 0 and 00 gauge, which lists more in depth descriptions, along with McEntarfer's book of Prewar Sets. It takes some reading of all the books, to get a true sense of what is described of certain items, plus determining the actual year items were offered. I never rely on just one book, and use all of them, when researching items for Prewar. I have the 1935, '36, and '37 catalogs, to further check what was offered, by those years.
The 1030 isn't really uncommon, because of how a set or outfit was put together. Some of the Sets, had a 1689T (non-whistle tender), as part of a set, where other sets had a 1689W (whistle tender), as part of the set. That is where the McEntarfer book comes in handy, where the actual components are listed as they were found in collectors sets, or listed in a catalog from that era. I was fortunate to find my books at decent prices, and judicial shopping.
The 1688/1688E locos from 1936 are easy to tell from the later issues, because of certain details that ONLY show up on the 1936 issues. The thin casting was only from 1936, and the 1937 and later issues were the thick casting. The 1936 issue has an open firebox wall, where you can see the motor while looking into the cab. The firebox wall was added, and the casting was made thicker in 1937 and later. There is a square roof hatch on top of the cab for '36, and gone on later issues. Some, but not all '36 issue will have a "winged keystone" above the headlight. The very first issued 1688E had 'Open forward facing windows' in the cab, which are Rare and hard to find. The "Lionel Jr." motors for the earliest issues from 1936 have wheels that have 8 spokes, which were holdovers from the Lionel-Ives motors. The later 1937 issues have wheels with 12 spokes, and the bottom plates show Lionel 027. You will find some motors with Lionel Jr. tags, and 12 spoke wheels, and vice-versa, with Lionel 027 tags and 8 spoke wheels. I have done an extensive research on the 1688/1688E locos, and personally have ALL the different body variations made from 1936-1941. Greenberg's book listed 8 variations (1688 number plates or 1688E number plates, Gun Metal Gray or Black, etc.). I came up with 18 variations. If it is a 1688 loco, I can answer any question that someone may have, including the 1668 or 1588 Clockwork locos, that used the same basic body mold.