Ahh Grasshopper...not a slap, but a gentile nudge to you
A couple of things... IPB=IPC=Parts Catalog. Illustrated Parts Breakdown/ Illustrated Parts Catalog. The format, for those not familiar, is the a/c is broken down in to various section, which are then broken down much farther. At that level, there will be an exploded drawing of a section or major assembly, with each part flagged by a item number. After the drawing will be a table that refers to that specific drawing, listing each part in flag number order. Each part listing will contain the flag number, the part drawing number, nomenclature, quantity used and type/version effectivity. The effectivity block can get complicated in a hurry, especially on wartime production aircraft. Where the a/c was produced in multiple plants, It will include model of a/c, production block number and serial number range it was used on. There are instance of having parts that are applicable to single s/n aircraft, so this can be confusing until you have worked with it some.
Something else that will help: Aircraft production drawings are broken down into a general sequence, with individual drawings not necessarily being in a cohesive numbering sequence. Some companies did do this, but not all. The basic numbering scheme follows this pattern: XX(X)-zzzzz(z)-pp(p)(T).
XX(X) will be the particular aircraft, such as Mustang, Harpoon ect...It will be either a 2 digit or 3 digit number
zzzzz(z) is the actual base part number of the individual part or assembly.
pp(p)(T) is the dash number of the part, if there is more than one version. Often there will be more than one version of the part. It is also used where the individual parts make up an assembly and are only shown on the assembly drawing itself and fabricated from there. The designator (T) is used where there are mirrored or handed parts. It will generally end up being an L, R, T or B, giving the relative location within the assembly.
So here is a partial number off of my Fairchild. I don't have the prefix, as my books are the factory preliminary ones and the prefix was not assigned at the time of publication. So, xxx-724204-1L, is a Fairchild AT-21 part, 72 denotes part of the tail, 4204-1 is the particular part within the tail and because it is handed, there is the L designator. Each company had their own way of handing parts numbering, but most do follow a similar style sequence.
End of old warbird blueprint class for this morning...... more to follow as I can put things together and as questions come up.

I'll have to get my wife to run me thru making powerpoint slides with all the little xx'es and oo'es and arrows and.... oh wait a minute, this isn't Alice's Restaurant... I'll have her show me how to add that stuff and I can make up some slides that will show lots of the information that is available on the drawings.