Question about crown for 9ct 1950s Omega cal 266

I'm looking for a correct specification crown for a c.1954 9ct yellow gold Omega. I had a new one fitted some time back which is too big and modern looking but was apparently the best the repairer, a vintage Omega specialist, could manage.

Watch details are:
- British case marked Dennison 13322 (I think, but looks like 13 6over7 22), then below that ALD 697376 (as before, looks like 697 6over7 76)
-hallmark: Birmingham 1954-5
-Cal: no.266

I am not sure of the crown thread/tap number or case stem tube diameter.

The Omega Vintage Database at omegawatches.com and ofrei.com were unable to help. Google has various images of watches like mine but the crowns seem to vary.

Using the Cousinsuk.com search facility I came upon this page:

https://www.cousinsuk.com/document/category/450.aspx

and, searching against the case number 13322, the PDF 'Omega 13322 BL' seems to refer to the crown fifth from bottom on the following page:

https://www.cousinsuk.com/catalog/watch-parts/omega-hermetic-crowns/omega-hermetic-crowns-5mm-diameter-over

which is this:

• Tap 12 (Ø1.20mm)
• Crown Ø5.00mm
• Pendant Tube Ø2.00mm
• Crown Depth 1.80mm
• Gold Plated
• Omega 35002SX

which seems to be the same as this one on ebay, that the seller says is suitable for a Cal 266:

http://www.ebay.co.uk/itm/1x-Omega-NOS-Yellow-Gold-Crown-and-Stem-for-Cal-260-269-280-286-30T1-30T2-/121231306681?pt=UK_Jewellery_Watches_WatchAccessories_SpareParts_SM&hash=item1c39f2efb9

All of which suggests this is the right one, but would I be better off buying a crown only or a crown and stem, and would the Cousins crown be genuine Omega new old stock?

I assume it's not really necessary to change the stem if the stem is OK, as well as being a simpler job.

I'd be grateful for any advice or comments.

Thanks.

Al - what tool do you use to cut the stem, so as to avoid damaging the start of the thread? When I cut small bolts to length, I always thread a nut onto the bolt first, so that I can turn it back off and re-form the thread after it has been cut. But I don't suppose that trick is applicable here 😉

Thanks for your replies. Would I need just the crown and the stem or is there another piece between that is required?

It's just the crown, and as Al says, a spare stem would be sensible. Were you intending to do the job yourself?

No, I'll ask someone to do it, I am an owner with no watchmaking skills. From what I gather, there's little or no advantage to getting a 'factory fitted' crown and stem combination which according to the seller can just be slotted into a cal 266 if the two correct parts can be got elsewhere, just screwed together and then slotted in. Thinking more about it, probably I should get the opinion of the man who will do the work - my reluctance so far is that it was done wrong last time by someone who maybe should have known better.

It would be a very good idea to involve your watchmaker at an early stage.

I am sure you are right, thanks again.