There are perceived anvils and then are well, actual anvils.
I am thinking she used the term "anvils" to describe large "vises". Alot of work trucks in remote oil and ranch areas have large vises on them to facilitate "on site" repairs when ever possible.
The vises are used to hold various things under repair or modification. Repairing / modifying can include bending the material, welding it, or...... beating into a new shape with a hammer.
Thinking she saw an vise holding an object being struck with a hammer, and concluded that it was an "anvil". Then again, its possible that some work trucks in remote areas have both vices and anvils attatched to them. Material can be heated with a torch, then pounded into a new shape on an miniature anvil.
I just dont see these things falling off truck that often though.