Looks gen, but with no better pics it's more guessing than fact. Markers look good, maybe have been relumed as the 12 is a bit wobbly. Just to give you an idea - Singer was one out of seven known dial makers. On most fake dials, the printers stamp or engrave Singer in the back - so Singers are the most common fakes. There are also Beyeler fakes - if yo ucan get a pic from the dial back side it will be easy to identify as gen or fake. Some makers only used number codes indeed during some periods. Just because there is no Singer stamp doesn't mean it is fake. Hold the watch under a very strong (like 500W) lamp or optimally under a Sodium-gas lamp. While there keep your eyes shut and after a few secs go see a completely dark room - what do you see? Probably the hands make this not work as they will glow extremely bright due to their SL coating.
@ Tribal - take a look at ND Trading site - http://ndtradingcorp.com/zen/index.php?mai...products_id=158 - there are 16800 and even 16660 rdials, but they are as most of their dials, poor attempts.