i've not seen a roman shield of that shape referenced anywhere. the std. roman scutum of the republican period was a taller one than the later imperial ones.
the legionary soldiers also tended to wear mail or scale armour rather than the segmented plate armour of imperial times. the imperial scutum:
movies tend to cut corners and flatten these rectangles, or even make them out of sheet metal (or plastic)
the more rectangular semi cylindrical ones came later, along with various refinements to the helmet, adding brow bars, neck guards which got bigger over time, etc.
cavalry carried a flat oval shield:
as did auxilliary cohorts
centurions would sometimes carry a similar oval shield in their legions colours.
signifers carried a smaller round shield that could be used in one hand.
praetorian cavalry units would sometimes carry the flattened hex shield:
their infantry would use the taller republican shaped scutum.
the scorpion was their favourite symbol.
late imperial units carrier the dished oval shields, after constantine with the chi-rho christian symbol. usually with the longer cavalry spatha as the gladius fell out of fashion. later as northern barbarian mercenaries replaced the disciplined romans, the round flat 'viking' shield and longsword became the norm in roman infantry, which by that time were inferior arms, bypassed in popularity by the cataphracti, heavily armoured horse archers based on the persian model.
the shield in question looks like a prop department's idea of local potentates local troops shield. the symbols somehow brings up visions of the maccabees who revolted against rome. the local hebrew vassal 'king' (herod?) at the time of jesus had his own household troops which would not have had roman pattern arms.