Short answer

Two different people search this term. One just bought a used 38mm Speedmaster and wants to know if it is genuine. The other wants a replica of that same watch. Both need the same starting fact: reference 323.10.38 is a 38mm automatic Speedmaster with a date window, not a Moonwatch Professional. Once you accept that, most of the usual "is this fake?" panic disappears, because you are no longer looking for details that never existed on this model.

What this reference is, and why it trips people up

The Speedmaster name covers everything from the hand-wound Moonwatch to mid-size automatics with a date. The 323.10.38 sits in the second group: steel case around 38mm, automatic chronograph, date, and a bracelet. It never had a hand-wound 1861 inside, and it does not carry Moonwatch caseback text. Buyers who assume every Speedmaster is a Moonwatch go hunting for the wrong tells, and that is where a lot of bad verdicts come from.

The checks that separate real from fake

Case proportions

Measure across the bezel, not the crown guards. If the case reads 40mm or more, it is not this reference no matter what the listing says. A large share of fakes start life as a generic 40mm chrono case with a Speedmaster dial dropped in.

Dial printing and layout

Look at the wordmark and the subdial rings under a loupe. On a genuine dial the printing has hard edges and consistent weight. On a copy the text looks slightly bold or slightly soft, the subdials sit too close to the center, and the date font is wrong. Date fonts are the single most common slip on 38mm Speedmaster replicas.

Hands and crystal

The hand stack should be level with clean lume fill. The crystal is sapphire with anti-reflective coating on the inside, so it goes nearly invisible at an angle instead of showing a blue or purple sheen on the surface.

Caseback and engraving

Reference numbers are laser cut and sharp. Fakes show shallow cuts, a font that does not match the reference, or a caseback lifted from a completely different Speedmaster model.

Movement

The most frequent fake is a quartz watch behind a display back. Wind it, set the date, run the chronograph, then reset it. A mechanical chrono snaps back to zero with force. Quartz resets with a small tick. If the seconds hand jumps once per second instead of sweeping, you have your answer without opening anything.

The seller tells you more than the watch

Ask for service history, ask to meet at a watchmaker, ask for the serial and reference together in one photo. Boxes and cards cost almost nothing to fake, so they prove little. A seller who stalls on an inspection is the real warning sign, not a polished bezel.

If you are shopping for a replica instead

Straight talk: 38mm Speedmaster replicas are far less common than Moonwatch replicas, and the ones that exist miss on case thickness, date font, and subdial spacing. That is the honest tradeoff at replica prices. Know which one you are buying, pay accordingly, and never pay genuine money for a copy.

Bottom line

Confirm the size, confirm the movement is mechanical, and confirm the reference matches the caseback. Those three checks catch most fakes of this reference before you ever get to the dial details.