Do I have tubular breasts? I am considering explanting now 25 years later. Will my outcome be really bad if they are tubular?

Thank you for the question and picture.
I think your old photo does demonstrate some of the characteristics seen with tuberous (constricted) breasts. For example, the distance from the areola to inframammary folds seems to be tight and relatively short.  Your inframammary folds seem to be widely spaced from the midline of your chest. The areola do demonstrate some features associated with tuberous breast such as  an increased width  and “puffiness”.Remember that your breasts will likely have changed significantly over the course of 25 years.  In other words, the old picture may not have much predictive value. Generally speaking, what your breasts will look like after explantation depends on several factors such as: the quality of skin elasticity (the better the elasticity the better the skin will bounce back), the size of the implants used (the larger the implant the more trouble you may have with redundant skin), and the amount of breast tissue present at this time (which may have changed since the time of your breast augmentation).
Life experience since your breast augmentation procedure, such as pregnancy or weight gain weight loss, will potentially influence the factors discussed above. If you take these factors into consideration and apply them to your specific circumstances you may get a good idea of what to expect after the implants are removed.
 Patience is definitely indicated after removal of breast implants; it will take many months/year for the skin to “bounce back” and for you to see the final appearance of the breasts.   In other words, it may take several months for swelling to completely resolve;  postoperative deformities may be more visible at that time.
In "borderline" cases where there is doubt whether breast lifting is necessary or not, I advise patients to undergo explantation only and to give their breasts the benefit of the doubt  before deciding whether breast lifting would be beneficial.  
I hope this helps. Best wishes. 

Regardless of pre-implant shape, having implants will stretch the skin.  Having excess skin combined with a paucity of breast tissue can leave the breasts deflated and ptotic.  A fat transfer at the time of explant can replace the missing implant volume optimizing the appearance of the post explant breast.