Any way to create this error in Greek?

[NaphtaliPress]

I think the intended word is "the particle therefore, οὖν". Correct? Both the original 1646 text I'm working with and the 1844 printing set it as in the attached image. TypeGreek.com won't let me replicate the error. Is there any way to do so, so I can indicate the error in a note? Or was this a past convention rather than an actual mistake?

 

[Phil D.]

ȱ
Maybe you could hijack this character from Livonian...

 

[NaphtaliPress]

mmh. It's not quite right. If it is just an old convention I see no reason to replicate it; but I don't know that.
ὖ vs. ȱ

 

[Phil D.]

mmh. It's not quite right.

Picky, picky, picky... You're not supposed to magnify it, you're supposed to reduce (obscure) it...

 

[Charles Johnson]

There is no way to type that.
Here is a resource on typing ancient Greek.
If you follow the procedure described there, it will allow you to type that accent with an upsilon but not with an omicron.

mmh. It's not quite right. If it is just an old convention I see no reason to replicate it; but I don't know that.
ὖ vs. ȱ

It is just an old convention though, not an error.

 

[NaphtaliPress]

It is just an old convention though, not an error.

This is good; I don't need to do anything about noting it then.