There are canon examples of {rav} being used by itself to indicate a minimum:
{Hung buv rav: patlh Hut} "Classified Level 9 and Above" (Bird of Prey poster)
{nen rav: chorgh ben} "Ages 8 to adult" (Klingon Monopoly)
I knew about those two, but they're phrased differently than the {rav/'aqroS} construction. The {rav/'aqroS} construction puts the {rav} before the value of the lower bound, and is used in a larger sentence. Those two examples have {rav} at the end of the thing whose bounds are being described, and are used in a sort of standalone "label noun phrase: value noun phrase" context. They're different enough from the {rav/'aqroS} construction that I didn't think they'd work so well as supporting evidence for using half of a {rav/'aqroS} construction by itself.
In every instance, {rav} precedes the value of the lower bound:
{[rav cha' 'uj] 'aqroS loS 'uj} (at least 2 ujes)
{[rav DaSjaj] 'aqroS buqjaj} (at least Monday, Monday at the earliest)
{QujwI' ghom [rav cha'] 'aqroS jav} (at least 2 players)
The examples in my previous email are just truncated versions of this pattern:
{Hung buv [rav patlh Hut]} (at least level 9)
{nen [rav chorgh ben]} (at least 8 years old)
The fact that a colon is placed after {rav} in some cases to indicate a label makes it *look* different, but punctuation isn't really part of the Klingon writing system. The pattern is still "(thing bounded) {rav} (lower bound value)".
I think the following sentences are grammatical, and follow the same grammar:
{rav cha' 'uj 'aqroS loS 'uj 'ab naQ} "the stick measures between 2 and 4 ujes"
{QujwI' ghom rav cha' 'aqroS jav wIpoQ} "we need a group of 2 to 6 players"
{QujwI' ghom rav cha' wIpoQ} "we need a group of at least 2 players"
{De'vam leghlu'meH, Hung buv rav patlh Hut poQlu'} "in order for one to see this data, security classification of at least level 9 is required"
--
De'vID