No. as in this case is a conjunction. From Wikitonary, one of the definitions of as is the following, which matches your use:
as Conjunction (dated)
Introducing a comparison with a hypothetical state (+ subjunctive); ‘as though’, ‘as if’. [to 19th century]
1526, William Tyndale, trans. Bible, Acts II:
- And sodenly there cam a sounde from heven as it had bene the commynge off a myghty wynde* [...].
c. 1616, William Shakespeare, King Henry VI part 2, First Folio 1623, I.1:
Oft haue I seene the haughty Cardinall, / More like a Souldier then a man o'th' Church, / As stout and proud as he were Lord of all [...].
This is one of the problems of reading very old texts - you will have to deal with the fact that dated English sometimes has slightly different usage and/or grammar to modern English.