Help needed on this Zenith Rainbow.

Request forum to help me with this Zenith Rainbow.

When i enlarge image, i can see there is 20 and 25 on the outside of outer chapter. Means 5 to 60 are written there, not tachymeter.

On the caseback, there is Rainbow, silhouette of a sailing boat and something like ACER (not ACIER).

Cant see any number.

It probably belonged to a pilot and got damaged in some action.

A similar Zenith dial but CHRONOGRAPH on dial, not El Primero is also attached. Hour markers are different here.

Can somebody help with the exact model? Its cal400. The spare dial i have is also attached, but hour markers are different.

I request help of forum in

1. Identifying this watch and a similar one with same back.

2. Advise on correct dial

3. Help on locating a steel bezel and hands for this.

TIA

For 1:

I assume the dial was white - Looks like a 53.0373/0473.400 or 41.0373/0473.400 / only difference 53 vs 41 is bracelet vs leather strap

2.
There is many different dials on the zenith rainbows. So far I have not seen one case back like this with the cheaply engraved "Acer" on any El Primero / Rainbow - but I am not an expert.
If there is no holes for pushers in the case it could be from the Zenith Elite Diver

3.
20.0143.400 or 20.0153.400 (swiss market only)
Case is gold plated for this reference and has a crystal caseback and uses the El Primero 400 movement - only 700 made in total and the case is very unusual for Zenith - I assume only used for 1 or 2 other references if ever and all gold plated. I don't know which hands and case in steel will fit

Thank you so much for your reply!

I dont think dial you have quoted is correct because when you enlarge my dial, you will find 25 written outside the outer chapter ring. SO it has second markere on the outside at the edges. Thus my Cal 400 case doesnt have inner Tachymetre but the outer rotatingTachymetre bezel.

I can also make out 20 outside hourmarker 4 (and 25 outside hourmarker 5). This the dial has to have that. Hence I have linked the other dial which reads "chronograph", not El Primero. It is one of the earliest Zenith Rainbow. I am uploading the case too here:

It has holes for pushers. Watchmaker says Rolex Daytona was designed after this type of Zenith watch, which ofcourse I dont know.

Can anybody help with Tachymetre bezel pl?

Would appreciate some help, Zenith lovers.