I mentioned this in an earlier topic and thought it deserved more discussion. RIC VII describes the reverse of the VICTORIAE LAETAE PRINC PERP coinage as "two Victories stg., facing one another, together holding shield inscribed VOT PR"; but the object must actually be a wreath.
You can see the wreath decoration at the top of the above example at around 11 and 1 o'clock. All VLPP's have these (except for a rare few), though not always so apparent. Shields do not have these (compare with the shield on the obverse of the VLPP above), but not all wreaths show these decorations or ties either.
The second coin below is a fairly standard depiction of a wreath, but without the top decoration/ ties; which is located at the bottom. Note how the VOT coinage also has a legend inscribed in the wreath, like the VLPP.
There was a series of coinage for Magnentius and Decentius that has a very similar reverse to the VLPP. The description from RIC VIII correctly calls the object a wreath- "two Victories holding wreath inscribed with VOT V MVLT X"