I've done this several times and it's always been welcomed. Also attended funerals of people I haven't seen in years. One was that of my first serious teenage boyfriend who died in his 40s. There were lots of people there from his past and his widow was comforted that we all remembered him. Also last year the funeral of my DDs best friend from school (also not been in touch with in recent years) age 39 and recently married. All the kids from their teens attended and her mum was overcome with thanks - she hadn't realised just how valued her DD had been. The boys (well, all now middle-aged men) also did two sponsored walks to raise funds for her 3-year old DD, my own DD travelled 200 miles to join them (and her mum and husband).
Unless circumstances are very different I imagine that knowing your memories of the person were fond ones is very comforting.