I don't think the lack of a countersigned agreement from your employer or you not receiving the $1 consideration will give you much of an argument against these assignments.
It's not clear that you even had to receive the countersigned agreements (do the assignments say so?), since assignments are one-way transactions anyway.
As for the $1, I think a judge would consider that payment a nominal gesture, since the real consideration (and your assignments may say as much) is your employment itself.
Also, general employment law says that anything you produce while in the employ of hyour company belongs to them.
Finally, the fact that some years have gone by since you signed the assignments, presumably without any assertion of ownership on your part, adds further strength to the employer's assertion of ownership.
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Unless you have a written employment agreement providing that you maintain ownership of the inventions that you created while employed, your inventions and patents belong to your employer and you have no legal interests or rights relating to them. Note that one of the amendments to patent law in the American Invents Acts allows patents to be prosecuted in the names of their owners rather than in the names of the individual inventors---in recognize of the fact that invention assignments have been much ado about nothing in most situations.