It's always likely mastereddy69 that if your machine hasn't got a vendor yet cast plates over the window, there's every likelihood it came from the factory that way.
The same could apply with the skill linkages. You may be trying to restore it to something it never was.
We sometimes get posts on here asking what the authentic colours were for bandits.
In the 60s I remember my Uncle taking delivery of new Sega bandits in primer. They were cheaper and many establishments wanted to paint them in their own club colours anyway.
I haven't got a clue.
Every Tura Bell I've owned had it, but it lines up with nothing on the inside.
My only suggestion is they used the same castings for the other bandit they made (can't think of its name, but it's also in Dieter's book) it had no jack pot and the bottom half was all vendor. In fact if you look carefully at The Tura you'll see where the middle is cut out by hand so the jack pot has space to fit.
Anyhow what I was going to say before I wandered off for a moment, perhaps the other machine had a coin view window that lined up. Just not on the Tura Bell.
I have just noticed that the well known dealer in Belgium Werner Paredis has a picture of a trailer load of parts and machines he bought a while back on his Facebook page and is loaded with Turas......maybe worth pinging him an email.....he is on the site as Coinopbelgium, but is not a contributor sadly ....