Forged document filed for first time by defendant

5 years ago

Defendant has mentioned in his written statement that he will produce a permission letter signed by landlord palintiff but in spite of plaintiff asking for inspection in 2010he did not produce it till 2018. Now during cross examination of plaintiff by court commissioner (Not in court but at home as plaintiff is bed ridden), he produced letter and asked plaintiff if sign is his to which plaintiff said yes. Defendant lawyer then asked plaintiff if he signed after reading contents and plaintiff said yes. Plaintiff lawyer objected that document cannot be produced now at this stage. But court. Commissioner took document and said she will submit to court and let judge decide on admission of document and also write down the objection of plaintiff lawyer.
Now plaintiff has realised that some words at the end of document have been added later. 
My question is...
1. Will court allow document to be exhibited 
2. If plaintiff moves application that document is forged forged then will court send to handwriting expert

Plaintiff has a report from private forensic handwriting expert that the words are added later