Short answer

"3rd generation" points at two different watches. On the original Speedmaster the term means the CK2915-3, the third version of the first Speedmaster reference from 1957. In the 1957 anniversary series it means the 2017 Trilogy model, reference 311.10.39.30.01.001, the third reissue of the 1957 design after 1997 and 2007. Fakes of the 2017 watch are common. Full copies of the CK2915 are rare, because the calibre 321 movement is hard to fake. Franken watches, built from real and fake parts, are the bigger problem for the CK2915.

Specs to compare

The 2017 Speedmaster 1957 Trilogy: steel case, 38.6 mm. Straight lugs. No crown guards. Broad arrow hour hand. Lollipop hand on the small seconds subdial at 9 o'clock. Black aluminum bezel insert with "Base 1000" and a dot over 90. Calibre 1861, hand wound, 18 jewels, 21,600 vph, about 48 hours of power reserve. Limited to 3,557 pieces. The caseback carries the number, for example 0123/3557.

The CK2915: 1957 case, calibre 321, "Base 1000" bezel, broad arrow hands. The reference was built in three versions, CK2915-1, CK2915-2 and CK2915-3. The changes between them are small. Collector sources do not agree on every detail, so read a specialist reference book before you buy one.

Case and size checks

Measure the case. A 1957 Speedmaster is 38.6 mm wide. Many fakes sit in a 42 mm case, the size of a later Speedmaster Professional. A 42 mm "1957" is wrong.

Look at the lugs. The 1957 case has straight lugs and a thin bezel. Later cases have twisted lugs and crown guards.

Weigh the watch. Steel and a hand wound chronograph movement give a set weight. A light case points to a plated brass body.

Dial and bezel checks

Bezel text: "Base 1000" with a dot over the 90. Fakes print "500" or set the dot in the wrong spot.

Dial print: "Omega" and "Speedmaster" sit below 12. Counters at 3, 6 and 9. "Swiss Made" under 6. The 2017 watch uses a vintage lume tone. Bright green lume points to a later fake dial.

Hands: broad arrow hour hand, baton minute hand, lollipop on the running seconds. Wrong hand shapes are the easiest tell in photos.

Movement checks

Ask for a photo of the movement. The 1861 is rhodium plated, 18 jewels, 21,600 vph. The rate does not settle the question, because the Seagull ST19 used in many fakes runs at the same rate. Check the finish, the shape of the balance bridge and the shock setting.

Quartz is an immediate fail. No Speedmaster from 1957 or from the 2017 run left the factory with a battery.

Papers and numbers

The 2017 watch came with a limited edition card, a pictograms card and a warranty card. The number on the caseback must match the cards. Omega can confirm a serial number through an authorized service center.

Prices move with the market. A low asking price on a 3,557 piece limited edition is a warning, not proof.

What photos cannot show

A photo cannot confirm the movement, the case metal or the serial number. For any watch above a few thousand dollars, pay for a hands-on check or buy from a dealer with a return policy.