have to admit that it sounds a bit weird though; as if a word for word translation, for a published copy or edition is not called a "kopya" (from copy) in turkish; or is the book an old manuscript? more context possible?

In english 'edition' is used more often when talking about a book. So the translation is 'Date of the first edition'

If you look at the inside cover of an English book, you may potentially see three dates :

First Published (self explanatory).
Second (and subsequent) Edition : i.e. republished with amendments.
Reprinted : used for subsequent print runs of a particular edition.

Given that the word 'kopyalamak' in Turkish can be used to mean 'to clone/replicate', I would suggest 'reprinted' as another possible alternative to those already proposed.

as "date of the first copy", if it is a publication, in this case the Turkish sentence should be as "date of the first edition"

Source: İngilizce – Türkçe Redhouse Sözlüğü

"Copy" => Asıl, kopya, numune, nüsha, müsvette, örnek suret; [Gazette] metin, yazı.

"Edition" => Baskı, tabı, bir kitabın bir defada basılması, bir kitabın bir defada basılma hali; bir kitabın bir defada basılan nüsha sayısı, tiraj.

Publication => ilan etme, yayım, yayın, yayınlama, yayınlanmış eser, yayma.

Source: Golden Dictionary İNGİLİZCE / TÜRKÇE
Issue => çıkarma, çıkma. çıkış, nüsha, piyasaya çıkarılma, sayı, yayınlama.

Source: İngilizce – Türkçe İktisadi Ticari Hukuki Terimler Sözlüğü
Reprint => yeniden tabetme; özellikle, bir ilanın gazetede veya mecmuada reklam amacıyla yeniden basılması