'Copy' a single Photo Cell- No!
But it is possible to 'Copy' a page layout, with your defined Photo/Text Cells-
1) Select one page, [Right-Click] > [Copy Layout], then select another page and [Right-Click] > [Paste Layout]. (Note: I find that I can only [Paste] to another selected page that already has a photo cell on the page- 'Paste' Doesn't work on a 'Blank' page.)
2) Select one page, [Right-Click] > [Save as Custom Page]. Thus you always have the Page layout available any time in the future. (Custom Pages are specific to the Book Size in which it was saved.)
Regards. My System: Lr-Classic 12.3 Photoshop 24.5, ACR 15.3.1, Lightroom 6.3.1, Lr-iOS 8.0.8, Bridge 13.0.3, Windows-11.