Posters in the past have been questioned by CIC as to why they referred to their significant other as a friend in the TRV application, so sometimes CIC will look at the previous application. The sponsorship app asks when the two people entered into a relationship, so on the off chance the office does indeed look, they may question the discrepancy (The TRV says they met earlier, but PR app says they met at a later date - which one is true?). It sounds like a small lie but you never know what will put a stick up CIC's butt.
For some reason my head made me think you told CIC you were in a relationship with your girlfriend for a long time when you applied for the TRV (years before you actually met). i don't know how I inferred that. If CIC asks, provide them with a compelling reason for the discrepancy. Make sure your other proof of relationship is airtight.