I recently acquired a 1929 Remington portable 3. I now have a 1, 2 & 3 of these, and it’s interesting to see the slight differences as the design was changed. The model 3 I found was missing a small stud from the carriage advance lever. I knocked out the embedded bit and hammered in a small nail in its place. That fixed the problem, and the typewriter is now working well – amazing for a 90 year old machine! The model 3 has a slightly wider platen than the #2, which was slightly wider than #1. The #1 had a simple advance mechanism that was much improved with the addition of the lever on model 2, which carried over to model 3. Model 2 had the original lifting typebars, which are gone in model 3, in favour of a low panel on the top front that conceal the slightly raised typebars. I assume this saved money in manufacturing, by eliminating the lifting mechanism. Something was lost however, in the way of a very interesting and unique feature. Model 3 also introduced a margin release key and fixed tabs, marked with a red keytop, as Olivetti became well known for later on with the Lettera 22. But Remington was first!