Looking at the two angels holding on the sides. Maybe I'm wrong, but to me, they look respectively holding:

• a sword: could be interpreted as a symbol of violence, power, and authority. It could be valor of courage, enforcement, conflict, and war! Maybe also justice and protection? Protection for whom? The People or the Government?
• a bit headgear: the horse itself was (and still) a potent symbol of power in 18th-century art. The bit is typically used to control a horse, and in this case, it could represent the government's role in maintaining order and control within society, but also restraint and order.

Just wondering if it could have any double/hidden meaning. As am not familiar with this artist, any other opinion on these details is more than welcome!