I agree w/ Stian. There are plenty of examples of pre-war original imports - in Norway through Sørensen & Balchen - of model 45" D, R and W; 61" E and 74" V and U models. These have 4 digit numbers. (After WWII the importer never resumed import of H-D due to the economic situation). But the pre-war activity shows nothing to support that the factory made "special export" series before WWII . Why should they bother anyway?
Chris talks about Olive green as an export color, it is correct that it was an "Export only" color for years after it was discontinued in the US - but that does not mean all export bikes was Olive green. It means that this color was availiable only on export markets, due to the fact that the buying public (at least in Scandinavia and The Netherlands) asked for this color - it had become synonymous with Harley during the 1920s. BUT the Olive green (at least in Norway, and I have the original brochures from 1937/1938/1939 to prove it) was offered BESIDE the factorys standard colors. In addition to "Export only" Olive green the color "Police Silver" was offered, and quite a few bikes had this color. So in 1937, the color availability in Norway is: The three "standard" colors of Teak Red, Bronze Brown and Delphine Blue PLUS "Silver" (Police Silver) AND the ever popular "Olive Green". So there was two extra color choices on export models in this country. This practice continued until import ceased due to WWII.
On the other side optional colors was not offered, the importer probably bought a batch of motorcycles in mixed colors and had them shipped - which took some time. No accessory groups was offered, all models had a standardized group for a given year. All 61OHV-s was delivered standard with jiffy-stand and tandem-seat as an example, while the 74 U was deliveded w/o jiffy stand, but with a luggage carrier. The importer obvously expected the 74 to pull side-hacks. Another peculiarity in the late 30s, no "L" models was offered, all models was medium compression - plain W, U and E models. Again something to do with the distance to Milwaukee I think.