A sealed knot supplier advertises a reproduction buckler suitable for use in 13-17th century battle reenactment,

As does this article:

My question is, was the buckler seen at all (or could it possibly have been seen) on the battlefields of the English civil war that late on? Perhaps soldiers too poor to purchase armour would keep their granddad's buckler around to pair with a sword when it came to the melee? Or perhaps it was a civilian weapon still around being taken onto the battlefield. Clearly it would not have been a common sight on the field as I haven't found any references/sources for it (although I may simply have not looked hard enough).

Can the history guru's help me out on this one?