Circa 1917 - Red litho with type A, M-style trucks, automatic couplers, embossed frame blackened wheels.

Circa 1918-22  Same as previous caboose except it has type B, M-style trucks 

Circa 1925-27 - Same as previous examples except this variation has type C, M-style trucks

Circa 1928-30  - The 67 caboose had few changes from 1917-1927, but from 1928-1930, you'll find numerous differences. The one below may have an older roof but normally you can spot a late caboose by it's type D, M-style trucks, red roof, and yellow lettering

This version has a peacock cupola roof. 

Here's a hard one to find, it's painted red with silver rubber stamped lettering and small (AF) wheels. Not the large lettering to CABOOSE, it's from the wide gauge car.

Circa 1928 - Ives lighted some of their No 67 caboose in 1928 only. 

Circa 1930 - A Lionel Body on an Ives frame, this is the only 6" caboose to have brass plates. The 67 lithographed caboose was still sold in 1930 and a couple we've found actually came in boxes marked No. 70.