On reading my question again, I realize that I made it seem more complicated than it really is. What I meant to ask is, when a family name is given and it is two surnames, should I assume the first applies to the husband and the second to the wife?
In my town that type of wording indicates an 'ossario' or family bone and ashes vault. The photos would have been transferred from the original niche and could be of either surname. On a regular tomb the full name and dates would be recorded and occasionally the married name if a woman.
At the cemetary I visited in Sulmona, the ossario was a collection of many unrelated families and there were no name placques. If you wanted to know whose remains were there, you needed to request this in the office.
Luke, that would have been my guess too, that, being listed first, LA VELLA was the husband's surname, while BALASSONE was the wife's. The only thing that had caused me to doubt this was the positionig of the photos above the names, which showed the wife's photo to the left of her husbands.
At this point I'm inclined to think that the positioning of the photos are not indicative of the positioning of the family names. Thanks.