From: Baidu: 您
“您”字并非属于通语字，这字原本为地方方言字-- The character “您” was not a standard character, it was originally a local dialect word
适用范围: -- Scope of application:
最初的方言字随普通话、通用书面传播到全国。-- The original dialect word spread throughout the country with Mandarin became standard writing.
您，第二人称词，敬称。(second-person pronoun, honorific)
南方语言（譬如：客家语、粤语、闽南语等）：(Southern dialects (for example: Hakka, Cantonese, Hokkien, etc.):
你，第二人称词。 (second-person pronoun)
From: WiKi: Bible translations into Chinese
The first translations may have been made as early as the 7th century AD, but the first printed translations appeared only in the nineteenth century
The Chinese Union Version is the predominant translation of the Bible into Chinese used by Chinese Protestants, first published in 1919.
From the research above:
您 was not used in Southern dialects before Mandarin education was pushed through the nation.
The Chinese Bible Union Version was published in 1919, predated the national standardization of Mandarin education. Therefore, 你 was still the only second-person pronoun in southern China. Since Christianity reached southern China before spreading to the north, it is reasonable to believe that the early Bible would use the local dialect 你 instead of the Mandarin 您
One more note: I have never seen 您 was used instead of 你 in any Hong Kong publication when I was young.